--- rest25/library/stdtypes.rst	2008-12-19 16:58:07.000000000 +0900
+++ rest262/library/stdtypes.rst	2009-04-07 00:06:53.000000000 +0900
@@ -1,44 +1,43 @@
+.. XXX: reference/datamodel and this have quite a few overlaps!
 
-.. _types:
+
+.. _bltin-types:
 
 **************
 Built-in Types
 **************
 
 The following sections describe the standard types that are built into the
 interpreter.
 
 .. note::
 
    Historically (until release 2.2), Python's built-in types have differed from
    user-defined types because it was not possible to use the built-in types as the
-   basis for object-oriented inheritance. This limitation does not exist any
-   longer.
+   basis for object-oriented inheritance. This limitation no longer
+   exists.
 
 .. index:: pair: built-in; types
 
 The principal built-in types are numerics, sequences, mappings, files, classes,
 instances and exceptions.
 
 .. index:: statement: print
 
 Some operations are supported by several object types; in particular,
 practically all objects can be compared, tested for truth value, and converted
 to a string (with the :func:`repr` function or the slightly different
 :func:`str` function).  The latter function is implicitly used when an object is
-written by the :keyword:`print` statement. (Information on the :keyword:`print`
-statement (XXX reference: ../ref/print.html) and other language statements can
-be found in the Python Reference Manual (XXX reference: ../ref/ref.html) and the
-Python Tutorial (XXX reference: ../tut/tut.html).)
+written by the :func:`print` function.
 
 
 .. _truth:
 
 Truth Value Testing
 ===================
 
 .. index::
    statement: if
    statement: while
    pair: truth; value
    pair: Boolean; operations
@@ -89,47 +88,52 @@
 ====================================================================
 
 .. index:: pair: Boolean; operations
 
 These are the Boolean operations, ordered by ascending priority:
 
 +-------------+---------------------------------+-------+
 | Operation   | Result                          | Notes |
 +=============+=================================+=======+
 | ``x or y``  | if *x* is false, then *y*, else | \(1)  |
 |             | *x*                             |       |
 +-------------+---------------------------------+-------+
-| ``x and y`` | if *x* is false, then *x*, else | \(1)  |
+| ``x and y`` | if *x* is false, then *x*, else | \(2)  |
 |             | *y*                             |       |
 +-------------+---------------------------------+-------+
-| ``not x``   | if *x* is false, then ``True``, | \(2)  |
+| ``not x``   | if *x* is false, then ``True``, | \(3)  |
 |             | else ``False``                  |       |
 +-------------+---------------------------------+-------+
 
 .. index::
    operator: and
    operator: or
    operator: not
 
 Notes:
 
 (1)
-   These only evaluate their second argument if needed for their outcome.
+   This is a short-circuit operator, so it only evaluates the second
+   argument if the first one is :const:`False`.
 
 (2)
+   This is a short-circuit operator, so it only evaluates the second
+   argument if the first one is :const:`True`.
+
+(3)
    ``not`` has a lower priority than non-Boolean operators, so ``not a == b`` is
    interpreted as ``not (a == b)``, and ``a == not b`` is a syntax error.
 
 
-.. _comparisons:
+.. _stdcomparisons:
 
 Comparisons
 ===========
 
 .. index:: pair: chaining; comparisons
 
 Comparison operations are supported by all objects.  They all have the same
 priority (which is higher than that of the Boolean operations). Comparisons can
 be chained arbitrarily; for example, ``x < y <= z`` is equivalent to ``x < y and
 y <= z``, except that *y* is evaluated only once (but in both cases *z* is not
 evaluated at all when ``x < y`` is found to be false).
 
@@ -141,64 +145,65 @@
 | ``<``      | strictly less than      |       |
 +------------+-------------------------+-------+
 | ``<=``     | less than or equal      |       |
 +------------+-------------------------+-------+
 | ``>``      | strictly greater than   |       |
 +------------+-------------------------+-------+
 | ``>=``     | greater than or equal   |       |
 +------------+-------------------------+-------+
 | ``==``     | equal                   |       |
 +------------+-------------------------+-------+
 | ``!=``     | not equal               | \(1)  |
 +------------+-------------------------+-------+
-| ``<>``     | not equal               | \(1)  |
-+------------+-------------------------+-------+
 | ``is``     | object identity         |       |
 +------------+-------------------------+-------+
 | ``is not`` | negated object identity |       |
 +------------+-------------------------+-------+
 
 .. index::
    pair: operator; comparison
    operator: ==
+   operator: <
+   operator: <=
+   operator: >
+   operator: >=
+   operator: !=
    operator: is
    operator: is not
 
-.. % XXX *All* others have funny characters < ! >
-
 Notes:
 
 (1)
-   ``<>`` and ``!=`` are alternate spellings for the same operator. ``!=`` is the
-   preferred spelling; ``<>`` is obsolescent.
+    ``!=`` can also be written ``<>``, but this is an obsolete usage
+    kept for backwards compatibility only. New code should always use
+    ``!=``.
 
 .. index::
    pair: object; numeric
    pair: objects; comparing
 
 Objects of different types, except different numeric types and different string
 types, never compare equal; such objects are ordered consistently but
 arbitrarily (so that sorting a heterogeneous array yields a consistent result).
 Furthermore, some types (for example, file objects) support only a degenerate
 notion of comparison where any two objects of that type are unequal.  Again,
 such objects are ordered arbitrarily but consistently. The ``<``, ``<=``, ``>``
 and ``>=`` operators will raise a :exc:`TypeError` exception when any operand is
 a complex number.
 
 .. index:: single: __cmp__() (instance method)
 
-Instances of a class normally compare as non-equal unless the class  defines the
-:meth:`__cmp__` method.  Refer to the Python Reference Manual (XXX reference:
-../ref/customization.html) for information on the use of this method to effect
-object comparisons.
+Instances of a class normally compare as non-equal unless the class defines the
+:meth:`__cmp__` method.  Refer to :ref:`customization`) for information on the
+use of this method to effect object comparisons.
 
 **Implementation note:** Objects of different types except numbers are ordered
 by their type names; objects of the same types that don't support proper
 comparison are ordered by their address.
 
 .. index::
    operator: in
    operator: not in
 
 Two more operations with the same syntactic priority, ``in`` and ``not in``, are
 supported only by sequence types (below).
 
@@ -232,228 +237,335 @@
 ``z.real`` and ``z.imag``.
 
 .. index::
    pair: numeric; literals
    pair: integer; literals
    triple: long; integer; literals
    pair: floating point; literals
    pair: complex number; literals
    pair: hexadecimal; literals
    pair: octal; literals
 
 Numbers are created by numeric literals or as the result of built-in functions
-and operators.  Unadorned integer literals (including hex and octal numbers)
-yield plain integers unless the value they denote is too large to be represented
-as a plain integer, in which case they yield a long integer.  Integer literals
-with an ``'L'`` or ``'l'`` suffix yield long integers (``'L'`` is preferred
-because ``1l`` looks too much like eleven!).  Numeric literals containing a
-decimal point or an exponent sign yield floating point numbers.  Appending
-``'j'`` or ``'J'`` to a numeric literal yields a complex number with a zero real
-part. A complex numeric literal is the sum of a real and an imaginary part.
+and operators.  Unadorned integer literals (including binary, hex, and octal
+numbers) yield plain integers unless the value they denote is too large to be
+represented as a plain integer, in which case they yield a long integer.
+Integer literals with an ``'L'`` or ``'l'`` suffix yield long integers (``'L'``
+is preferred because ``1l`` looks too much like eleven!).  Numeric literals
+containing a decimal point or an exponent sign yield floating point numbers.
+Appending ``'j'`` or ``'J'`` to a numeric literal yields a complex number with a
+zero real part. A complex numeric literal is the sum of a real and an imaginary
+part.
 
 .. index::
    single: arithmetic
    builtin: int
    builtin: long
    builtin: float
    builtin: complex
 
 Python fully supports mixed arithmetic: when a binary arithmetic operator has
 operands of different numeric types, the operand with the "narrower" type is
 widened to that of the other, where plain integer is narrower than long integer
 is narrower than floating point is narrower than complex. Comparisons between
 numbers of mixed type use the same rule. [#]_ The constructors :func:`int`,
 :func:`long`, :func:`float`, and :func:`complex` can be used to produce numbers
 of a specific type.
 
-All numeric types (except complex) support the following operations, sorted by
-ascending priority (operations in the same box have the same priority; all
-numeric operations have a higher priority than comparison operations):
+All builtin numeric types support the following operations. See
+:ref:`power` and later sections for the operators' priorities.
 
 +--------------------+---------------------------------+--------+
 | Operation          | Result                          | Notes  |
 +====================+=================================+========+
 | ``x + y``          | sum of *x* and *y*              |        |
 +--------------------+---------------------------------+--------+
 | ``x - y``          | difference of *x* and *y*       |        |
 +--------------------+---------------------------------+--------+
 | ``x * y``          | product of *x* and *y*          |        |
 +--------------------+---------------------------------+--------+
 | ``x / y``          | quotient of *x* and *y*         | \(1)   |
 +--------------------+---------------------------------+--------+
-| ``x // y``         | (floored) quotient of *x* and   | \(5)   |
+| ``x // y``         | (floored) quotient of *x* and   | (4)(5) |
 |                    | *y*                             |        |
 +--------------------+---------------------------------+--------+
 | ``x % y``          | remainder of ``x / y``          | \(4)   |
 +--------------------+---------------------------------+--------+
 | ``-x``             | *x* negated                     |        |
 +--------------------+---------------------------------+--------+
 | ``+x``             | *x* unchanged                   |        |
 +--------------------+---------------------------------+--------+
-| ``abs(x)``         | absolute value or magnitude of  |        |
+| ``abs(x)``         | absolute value or magnitude of  | \(3)   |
 |                    | *x*                             |        |
 +--------------------+---------------------------------+--------+
 | ``int(x)``         | *x* converted to integer        | \(2)   |
 +--------------------+---------------------------------+--------+
 | ``long(x)``        | *x* converted to long integer   | \(2)   |
 +--------------------+---------------------------------+--------+
-| ``float(x)``       | *x* converted to floating point |        |
+| ``float(x)``       | *x* converted to floating point | \(6)   |
 +--------------------+---------------------------------+--------+
 | ``complex(re,im)`` | a complex number with real part |        |
 |                    | *re*, imaginary part *im*.      |        |
 |                    | *im* defaults to zero.          |        |
 +--------------------+---------------------------------+--------+
 | ``c.conjugate()``  | conjugate of the complex number |        |
-|                    | *c*                             |        |
+|                    | *c*. (Identity on real numbers) |        |
 +--------------------+---------------------------------+--------+
 | ``divmod(x, y)``   | the pair ``(x // y, x % y)``    | (3)(4) |
 +--------------------+---------------------------------+--------+
-| ``pow(x, y)``      | *x* to the power *y*            |        |
+| ``pow(x, y)``      | *x* to the power *y*            | (3)(7) |
 +--------------------+---------------------------------+--------+
-| ``x ** y``         | *x* to the power *y*            |        |
+| ``x ** y``         | *x* to the power *y*            | \(7)   |
 +--------------------+---------------------------------+--------+
 
 .. index::
    triple: operations on; numeric; types
    single: conjugate() (complex number method)
 
 Notes:
 
 (1)
    .. index::
       pair: integer; division
       triple: long; integer; division
 
    For (plain or long) integer division, the result is an integer. The result is
    always rounded towards minus infinity: 1/2 is 0, (-1)/2 is -1, 1/(-2) is -1, and
    (-1)/(-2) is 0.  Note that the result is a long integer if either operand is a
    long integer, regardless of the numeric value.
 
 (2)
    .. index::
       module: math
       single: floor() (in module math)
       single: ceil() (in module math)
+      single: trunc() (in module math)
       pair: numeric; conversions
-      pair: C; language
 
-   Conversion from floating point to (long or plain) integer may round or truncate
-   as in C; see functions :func:`floor` and :func:`ceil` in the :mod:`math` module
-   for well-defined conversions.
+   Conversion from floats using :func:`int` or :func:`long` truncates toward
+   zero like the related function, :func:`math.trunc`.  Use the function
+   :func:`math.floor` to round downward and :func:`math.ceil` to round
+   upward.
 
 (3)
-   See section :ref:`built-in-funcs`, "Built-in Functions," for a full description.
+   See :ref:`built-in-funcs` for a full description.
 
 (4)
    Complex floor division operator, modulo operator, and :func:`divmod`.
 
    .. deprecated:: 2.3
       Instead convert to float using :func:`abs` if appropriate.
 
 (5)
    Also referred to as integer division.  The resultant value is a whole integer,
    though the result's type is not necessarily int.
 
-.. % XXXJH exceptions: overflow (when? what operations?) zerodivision
+(6)
+   float also accepts the strings "nan" and "inf" with an optional prefix "+"
+   or "-" for Not a Number (NaN) and positive or negative infinity.
+
+   .. versionadded:: 2.6
+
+(7)
+   Python defines ``pow(0, 0)`` and ``0 ** 0`` to be ``1``, as is common for
+   programming languages.
+
+All :class:`numbers.Real` types (:class:`int`, :class:`long`, and
+:class:`float`) also include the following operations:
+
++--------------------+------------------------------------+--------+
+| Operation          | Result                             | Notes  |
++====================+====================================+========+
+| ``math.trunc(x)``  | *x* truncated to Integral          |        |
++--------------------+------------------------------------+--------+
+| ``round(x[, n])``  | *x* rounded to n digits,           |        |
+|                    | rounding half to even. If n is     |        |
+|                    | omitted, it defaults to 0.         |        |
++--------------------+------------------------------------+--------+
+| ``math.floor(x)``  | the greatest integral float <= *x* |        |
++--------------------+------------------------------------+--------+
+| ``math.ceil(x)``   | the least integral float >= *x*    |        |
++--------------------+------------------------------------+--------+
+
+.. XXXJH exceptions: overflow (when? what operations?) zerodivision
 
 
 .. _bitstring-ops:
 
 Bit-string Operations on Integer Types
 --------------------------------------
 
-.. _bit-string operations:
+.. _bit-string-operations:
 
 Plain and long integer types support additional operations that make sense only
 for bit-strings.  Negative numbers are treated as their 2's complement value
 (for long integers, this assumes a sufficiently large number of bits that no
 overflow occurs during the operation).
 
-The priorities of the binary bit-wise operations are all lower than the numeric
+The priorities of the binary bitwise operations are all lower than the numeric
 operations and higher than the comparisons; the unary operation ``~`` has the
 same priority as the other unary numeric operations (``+`` and ``-``).
 
-This table lists the bit-string operations sorted in ascending priority
-(operations in the same box have the same priority):
+This table lists the bit-string operations sorted in ascending priority:
 
 +------------+--------------------------------+----------+
 | Operation  | Result                         | Notes    |
 +============+================================+==========+
 | ``x | y``  | bitwise :dfn:`or` of *x* and   |          |
 |            | *y*                            |          |
 +------------+--------------------------------+----------+
 | ``x ^ y``  | bitwise :dfn:`exclusive or` of |          |
 |            | *x* and *y*                    |          |
 +------------+--------------------------------+----------+
 | ``x & y``  | bitwise :dfn:`and` of *x* and  |          |
 |            | *y*                            |          |
 +------------+--------------------------------+----------+
-| ``x << n`` | *x* shifted left by *n* bits   | (1), (2) |
+| ``x << n`` | *x* shifted left by *n* bits   | (1)(2)   |
 +------------+--------------------------------+----------+
-| ``x >> n`` | *x* shifted right by *n* bits  | (1), (3) |
+| ``x >> n`` | *x* shifted right by *n* bits  | (1)(3)   |
 +------------+--------------------------------+----------+
 | ``~x``     | the bits of *x* inverted       |          |
 +------------+--------------------------------+----------+
 
 .. index::
    triple: operations on; integer; types
    pair: bit-string; operations
    pair: shifting; operations
    pair: masking; operations
 
 Notes:
 
 (1)
    Negative shift counts are illegal and cause a :exc:`ValueError` to be raised.
 
 (2)
-   A left shift by *n* bits is equivalent to multiplication by ``pow(2, n)``
-   without overflow check.
+   A left shift by *n* bits is equivalent to multiplication by ``pow(2, n)``.  A
+   long integer is returned if the result exceeds the range of plain integers.
 
 (3)
-   A right shift by *n* bits is equivalent to division by ``pow(2, n)`` without
-   overflow check.
+   A right shift by *n* bits is equivalent to division by ``pow(2, n)``.
+
+
+Additional Methods on Float
+---------------------------
+
+The float type has some additional methods.
+
+.. method:: float.as_integer_ratio()
+
+    Return a pair of integers whose ratio is exactly equal to the
+    original float and with a positive denominator.  Raises
+    :exc:`OverflowError` on infinities and a :exc:`ValueError` on
+    NaNs.
+
+    .. versionadded:: 2.6
+
+Two methods support conversion to
+and from hexadecimal strings.  Since Python's floats are stored
+internally as binary numbers, converting a float to or from a
+*decimal* string usually involves a small rounding error.  In
+contrast, hexadecimal strings allow exact representation and
+specification of floating-point numbers.  This can be useful when
+debugging, and in numerical work.
+
+
+.. method:: float.hex()
+
+   Return a representation of a floating-point number as a hexadecimal
+   string.  For finite floating-point numbers, this representation
+   will always include a leading ``0x`` and a trailing ``p`` and
+   exponent.
+
+   .. versionadded:: 2.6
+
+
+.. method:: float.fromhex(s)
+
+   Class method to return the float represented by a hexadecimal
+   string *s*.  The string *s* may have leading and trailing
+   whitespace.
+
+   .. versionadded:: 2.6
+
+
+Note that :meth:`float.hex` is an instance method, while
+:meth:`float.fromhex` is a class method.
+
+A hexadecimal string takes the form::
+
+   [sign] ['0x'] integer ['.' fraction] ['p' exponent]
+
+where the optional ``sign`` may by either ``+`` or ``-``, ``integer``
+and ``fraction`` are strings of hexadecimal digits, and ``exponent``
+is a decimal integer with an optional leading sign.  Case is not
+significant, and there must be at least one hexadecimal digit in
+either the integer or the fraction.  This syntax is similar to the
+syntax specified in section 6.4.4.2 of the C99 standard, and also to
+the syntax used in Java 1.5 onwards.  In particular, the output of
+:meth:`float.hex` is usable as a hexadecimal floating-point literal in
+C or Java code, and hexadecimal strings produced by C's ``%a`` format
+character or Java's ``Double.toHexString`` are accepted by
+:meth:`float.fromhex`.
+
+
+Note that the exponent is written in decimal rather than hexadecimal,
+and that it gives the power of 2 by which to multiply the coefficient.
+For example, the hexadecimal string ``0x3.a7p10`` represents the
+floating-point number ``(3 + 10./16 + 7./16**2) * 2.0**10``, or
+``3740.0``::
+
+   >>> float.fromhex('0x3.a7p10')
+   3740.0
+
+
+Applying the reverse conversion to ``3740.0`` gives a different
+hexadecimal string representing the same number::
+
+   >>> float.hex(3740.0)
+   '0x1.d380000000000p+11'
 
 
 .. _typeiter:
 
 Iterator Types
 ==============
 
 .. versionadded:: 2.2
 
 .. index::
    single: iterator protocol
    single: protocol; iterator
    single: sequence; iteration
    single: container; iteration over
 
 Python supports a concept of iteration over containers.  This is implemented
 using two distinct methods; these are used to allow user-defined classes to
 support iteration.  Sequences, described below in more detail, always support
 the iteration methods.
 
 One method needs to be defined for container objects to provide iteration
 support:
 
+.. XXX duplicated in reference/datamodel!
 
 .. method:: container.__iter__()
 
    Return an iterator object.  The object is required to support the iterator
-   protocol described below.  If a container supports different types of iteration,
-   additional methods can be provided to specifically request iterators for those
-   iteration types.  (An example of an object supporting multiple forms of
-   iteration would be a tree structure which supports both breadth-first and depth-
-   first traversal.)  This method corresponds to the :attr:`tp_iter` slot of the
-   type structure for Python objects in the Python/C API.
+   protocol described below.  If a container supports different types of
+   iteration, additional methods can be provided to specifically request
+   iterators for those iteration types.  (An example of an object supporting
+   multiple forms of iteration would be a tree structure which supports both
+   breadth-first and depth-first traversal.)  This method corresponds to the
+   :attr:`tp_iter` slot of the type structure for Python objects in the Python/C
+   API.
 
 The iterator objects themselves are required to support the following two
 methods, which together form the :dfn:`iterator protocol`:
 
 
 .. method:: iterator.__iter__()
 
    Return the iterator object itself.  This is required to allow both containers
    and iterators to be used with the :keyword:`for` and :keyword:`in` statements.
    This method corresponds to the :attr:`tp_iter` slot of the type structure for
    Python objects in the Python/C API.
 
@@ -467,111 +579,117 @@
 
 Python defines several iterator objects to support iteration over general and
 specific sequence types, dictionaries, and other more specialized forms.  The
 specific types are not important beyond their implementation of the iterator
 protocol.
 
 The intention of the protocol is that once an iterator's :meth:`next` method
 raises :exc:`StopIteration`, it will continue to do so on subsequent calls.
 Implementations that do not obey this property are deemed broken.  (This
 constraint was added in Python 2.3; in Python 2.2, various iterators are broken
 according to this rule.)
 
-Python's generators provide a convenient way to implement the iterator protocol.
-If a container object's :meth:`__iter__` method is implemented as a generator,
-it will automatically return an iterator object (technically, a generator
-object) supplying the :meth:`__iter__` and :meth:`next` methods.
+Python's :term:`generator`\s provide a convenient way to implement the iterator
+protocol.  If a container object's :meth:`__iter__` method is implemented as a
+generator, it will automatically return an iterator object (technically, a
+generator object) supplying the :meth:`__iter__` and :meth:`next` methods.
 
 
 .. _typesseq:
 
 Sequence Types --- :class:`str`, :class:`unicode`, :class:`list`, :class:`tuple`, :class:`buffer`, :class:`xrange`
 ==================================================================================================================
 
 There are six sequence types: strings, Unicode strings, lists, tuples, buffers,
 and xrange objects.
 
+For other containers see the built in :class:`dict` and :class:`set` classes,
+and the :mod:`collections` module.
+
+
 .. index::
    object: sequence
    object: string
    object: Unicode
    object: tuple
    object: list
+   object: buffer
+   object: xrange
 
 String literals are written in single or double quotes: ``'xyzzy'``,
-``"frobozz"``.  See chapter 2 of the Python Reference Manual (XXX reference:
-../ref/strings.html) for more about string literals.  Unicode strings are much
-like strings, but are specified in the syntax using a preceding ``'u'``
-character: ``u'abc'``, ``u"def"``.  Lists are constructed with square brackets,
-separating items with commas: ``[a, b, c]``.  Tuples are constructed by the
-comma operator (not within square brackets), with or without enclosing
-parentheses, but an empty tuple must have the enclosing parentheses, such as
-``a, b, c`` or ``()``.  A single item tuple must have a trailing comma, such as
-``(d,)``.
-
-.. index::
-   builtin: buffer
-   object: buffer
+``"frobozz"``.  See :ref:`strings` for more about string literals.
+Unicode strings are much like strings, but are specified in the syntax
+using a preceding ``'u'`` character: ``u'abc'``, ``u"def"``. In addition
+to the functionality described here, there are also string-specific
+methods described in the :ref:`string-methods` section. Lists are
+constructed with square brackets, separating items with commas: ``[a, b, c]``.
+Tuples are constructed by the comma operator (not within square
+brackets), with or without enclosing parentheses, but an empty tuple
+must have the enclosing parentheses, such as ``a, b, c`` or ``()``.  A
+single item tuple must have a trailing comma, such as ``(d,)``.
 
 Buffer objects are not directly supported by Python syntax, but can be created
 by calling the builtin function :func:`buffer`.  They don't support
 concatenation or repetition.
 
-.. index::
-   builtin: xrange
-   object: xrange
-
-Xrange objects are similar to buffers in that there is no specific syntax to
+Objects of type xrange are similar to buffers in that there is no specific syntax to
 create them, but they are created using the :func:`xrange` function.  They don't
 support slicing, concatenation or repetition, and using ``in``, ``not in``,
 :func:`min` or :func:`max` on them is inefficient.
 
 Most sequence types support the following operations.  The ``in`` and ``not in``
 operations have the same priorities as the comparison operations.  The ``+`` and
 ``*`` operations have the same priority as the corresponding numeric operations.
-[#]_
+[#]_ Additional methods are provided for :ref:`typesseq-mutable`.
 
 This table lists the sequence operations sorted in ascending priority
 (operations in the same box have the same priority).  In the table, *s* and *t*
 are sequences of the same type; *n*, *i* and *j* are integers:
 
 +------------------+--------------------------------+----------+
 | Operation        | Result                         | Notes    |
 +==================+================================+==========+
 | ``x in s``       | ``True`` if an item of *s* is  | \(1)     |
 |                  | equal to *x*, else ``False``   |          |
 +------------------+--------------------------------+----------+
 | ``x not in s``   | ``False`` if an item of *s* is | \(1)     |
 |                  | equal to *x*, else ``True``    |          |
 +------------------+--------------------------------+----------+
 | ``s + t``        | the concatenation of *s* and   | \(6)     |
 |                  | *t*                            |          |
 +------------------+--------------------------------+----------+
 | ``s * n, n * s`` | *n* shallow copies of *s*      | \(2)     |
 |                  | concatenated                   |          |
 +------------------+--------------------------------+----------+
 | ``s[i]``         | *i*'th item of *s*, origin 0   | \(3)     |
 +------------------+--------------------------------+----------+
-| ``s[i:j]``       | slice of *s* from *i* to *j*   | (3), (4) |
+| ``s[i:j]``       | slice of *s* from *i* to *j*   | (3)(4)   |
 +------------------+--------------------------------+----------+
-| ``s[i:j:k]``     | slice of *s* from *i* to *j*   | (3), (5) |
+| ``s[i:j:k]``     | slice of *s* from *i* to *j*   | (3)(5)   |
 |                  | with step *k*                  |          |
 +------------------+--------------------------------+----------+
 | ``len(s)``       | length of *s*                  |          |
 +------------------+--------------------------------+----------+
 | ``min(s)``       | smallest item of *s*           |          |
 +------------------+--------------------------------+----------+
 | ``max(s)``       | largest item of *s*            |          |
 +------------------+--------------------------------+----------+
 
+Sequence types also support comparisons. In particular, tuples and lists
+are compared lexicographically by comparing corresponding
+elements. This means that to compare equal, every element must compare
+equal and the two sequences must be of the same type and have the same
+length. (For full details see :ref:`comparisons` in the language
+reference.)
+
 .. index::
    triple: operations on; sequence; types
    builtin: len
    builtin: min
    builtin: max
    pair: concatenation; operation
    pair: repetition; operation
    pair: subscript; operation
    pair: slice; operation
    pair: extended slice; operation
    operator: in
    operator: not in
@@ -579,60 +697,60 @@
 Notes:
 
 (1)
    When *s* is a string or Unicode string object the ``in`` and ``not in``
    operations act like a substring test.  In Python versions before 2.3, *x* had to
    be a string of length 1. In Python 2.3 and beyond, *x* may be a string of any
    length.
 
 (2)
    Values of *n* less than ``0`` are treated as ``0`` (which yields an empty
    sequence of the same type as *s*).  Note also that the copies are shallow;
    nested structures are not copied.  This often haunts new Python programmers;
-   consider::
+   consider:
 
       >>> lists = [[]] * 3
       >>> lists
       [[], [], []]
       >>> lists[0].append(3)
       >>> lists
       [[3], [3], [3]]
 
    What has happened is that ``[[]]`` is a one-element list containing an empty
    list, so all three elements of ``[[]] * 3`` are (pointers to) this single empty
    list.  Modifying any of the elements of ``lists`` modifies this single list.
-   You can create a list of different lists this way::
+   You can create a list of different lists this way:
 
       >>> lists = [[] for i in range(3)]
       >>> lists[0].append(3)
       >>> lists[1].append(5)
       >>> lists[2].append(7)
       >>> lists
       [[3], [5], [7]]
 
 (3)
    If *i* or *j* is negative, the index is relative to the end of the string:
    ``len(s) + i`` or ``len(s) + j`` is substituted.  But note that ``-0`` is still
    ``0``.
 
 (4)
    The slice of *s* from *i* to *j* is defined as the sequence of items with index
    *k* such that ``i <= k < j``.  If *i* or *j* is greater than ``len(s)``, use
    ``len(s)``.  If *i* is omitted or ``None``, use ``0``.  If *j* is omitted or
    ``None``, use ``len(s)``.  If *i* is greater than or equal to *j*, the slice is
    empty.
 
 (5)
    The slice of *s* from *i* to *j* with step *k* is defined as the sequence of
-   items with index  ``x = i + n*k`` such that 0 ≤n < (j-i)/(k).  In other words,
+   items with index  ``x = i + n*k`` such that ``0 <= n < (j-i)/k``.  In other words,
    the indices are ``i``, ``i+k``, ``i+2*k``, ``i+3*k`` and so on, stopping when
    *j* is reached (but never including *j*).  If *i* or *j* is greater than
    ``len(s)``, use ``len(s)``.  If *i* or *j* are omitted or ``None``, they become
    "end" values (which end depends on the sign of *k*).  Note, *k* cannot be zero.
    If *k* is ``None``, it is treated like ``1``.
 
 (6)
    If *s* and *t* are both strings, some Python implementations such as CPython can
    usually perform an in-place optimization for assignments of the form ``s=s+t``
    or ``s+=t``.  When applicable, this optimization makes quadratic run-time much
    less likely.  This optimization is both version and implementation dependent.
    For performance sensitive code, it is preferable to use the :meth:`str.join`
@@ -641,392 +759,454 @@
 
    .. versionchanged:: 2.4
       Formerly, string concatenation never occurred in-place.
 
 
 .. _string-methods:
 
 String Methods
 --------------
 
 .. index:: pair: string; methods
 
-These are the string methods which both 8-bit strings and Unicode objects
-support:
+Below are listed the string methods which both 8-bit strings and Unicode objects
+support. Note that none of these methods take keyword arguments.
 
+In addition, Python's strings support the sequence type methods
+described in the :ref:`typesseq` section. To output formatted strings
+use template strings or the ``%`` operator described in the
+:ref:`string-formatting` section. Also, see the :mod:`re` module for
+string functions based on regular expressions.
 
-.. method:: string.capitalize()
+.. method:: str.capitalize()
 
    Return a copy of the string with only its first character capitalized.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.center(width[, fillchar])
+.. method:: str.center(width[, fillchar])
 
    Return centered in a string of length *width*. Padding is done using the
    specified *fillchar* (default is a space).
 
    .. versionchanged:: 2.4
       Support for the *fillchar* argument.
 
 
-.. method:: string.count(sub[, start[, end]])
+.. method:: str.count(sub[, start[, end]])
 
-   Return the number of occurrences of substring *sub* in string S\
-   ``[start:end]``.  Optional arguments *start* and *end* are interpreted as in
-   slice notation.
+   Return the number of non-overlapping occurrences of substring *sub* in the
+   range [*start*, *end*].  Optional arguments *start* and *end* are
+   interpreted as in slice notation.
 
 
-.. method:: string.decode([encoding[, errors]])
+.. method:: str.decode([encoding[, errors]])
 
    Decodes the string using the codec registered for *encoding*. *encoding*
    defaults to the default string encoding.  *errors* may be given to set a
    different error handling scheme.  The default is ``'strict'``, meaning that
    encoding errors raise :exc:`UnicodeError`.  Other possible values are
    ``'ignore'``, ``'replace'`` and any other name registered via
    :func:`codecs.register_error`, see section :ref:`codec-base-classes`.
 
    .. versionadded:: 2.2
 
    .. versionchanged:: 2.3
       Support for other error handling schemes added.
 
 
-.. method:: string.encode([encoding[,errors]])
+.. method:: str.encode([encoding[,errors]])
 
    Return an encoded version of the string.  Default encoding is the current
    default string encoding.  *errors* may be given to set a different error
    handling scheme.  The default for *errors* is ``'strict'``, meaning that
    encoding errors raise a :exc:`UnicodeError`.  Other possible values are
    ``'ignore'``, ``'replace'``, ``'xmlcharrefreplace'``, ``'backslashreplace'`` and
    any other name registered via :func:`codecs.register_error`, see section
    :ref:`codec-base-classes`. For a list of possible encodings, see section
    :ref:`standard-encodings`.
 
    .. versionadded:: 2.0
 
    .. versionchanged:: 2.3
       Support for ``'xmlcharrefreplace'`` and ``'backslashreplace'`` and other error
       handling schemes added.
 
 
-.. method:: string.endswith(suffix[, start[, end]])
+.. method:: str.endswith(suffix[, start[, end]])
 
    Return ``True`` if the string ends with the specified *suffix*, otherwise return
    ``False``.  *suffix* can also be a tuple of suffixes to look for.  With optional
    *start*, test beginning at that position.  With optional *end*, stop comparing
    at that position.
 
    .. versionchanged:: 2.5
       Accept tuples as *suffix*.
 
 
-.. method:: string.expandtabs([tabsize])
+.. method:: str.expandtabs([tabsize])
 
-   Return a copy of the string where all tab characters are expanded using spaces.
-   If *tabsize* is not given, a tab size of ``8`` characters is assumed.
+   Return a copy of the string where all tab characters are replaced by one or
+   more spaces, depending on the current column and the given tab size.  The
+   column number is reset to zero after each newline occurring in the string.
+   If *tabsize* is not given, a tab size of ``8`` characters is assumed.  This
+   doesn't understand other non-printing characters or escape sequences.
 
 
-.. method:: string.find(sub[, start[, end]])
+.. method:: str.find(sub[, start[, end]])
 
    Return the lowest index in the string where substring *sub* is found, such that
    *sub* is contained in the range [*start*, *end*].  Optional arguments *start*
    and *end* are interpreted as in slice notation.  Return ``-1`` if *sub* is not
    found.
 
 
-.. method:: string.index(sub[, start[, end]])
+.. method:: str.format(format_string, *args, **kwargs)
+
+   Perform a string formatting operation.  The *format_string* argument can
+   contain literal text or replacement fields delimited by braces ``{}``.  Each
+   replacement field contains either the numeric index of a positional argument,
+   or the name of a keyword argument.  Returns a copy of *format_string* where
+   each replacement field is replaced with the string value of the corresponding
+   argument.
+
+      >>> "The sum of 1 + 2 is {0}".format(1+2)
+      'The sum of 1 + 2 is 3'
+
+   See :ref:`formatstrings` for a description of the various formatting options
+   that can be specified in format strings.
+
+   This method of string formatting is the new standard in Python 3.0, and
+   should be preferred to the ``%`` formatting described in
+   :ref:`string-formatting` in new code.
+
+   .. versionadded:: 2.6
+
+
+.. method:: str.index(sub[, start[, end]])
 
    Like :meth:`find`, but raise :exc:`ValueError` when the substring is not found.
 
 
-.. method:: string.isalnum()
+.. method:: str.isalnum()
 
    Return true if all characters in the string are alphanumeric and there is at
    least one character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.isalpha()
+.. method:: str.isalpha()
 
    Return true if all characters in the string are alphabetic and there is at least
    one character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.isdigit()
+.. method:: str.isdigit()
 
    Return true if all characters in the string are digits and there is at least one
    character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.islower()
+.. method:: str.islower()
 
    Return true if all cased characters in the string are lowercase and there is at
    least one cased character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.isspace()
+.. method:: str.isspace()
 
    Return true if there are only whitespace characters in the string and there is
    at least one character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.istitle()
+.. method:: str.istitle()
 
    Return true if the string is a titlecased string and there is at least one
    character, for example uppercase characters may only follow uncased characters
    and lowercase characters only cased ones.  Return false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.isupper()
+.. method:: str.isupper()
 
    Return true if all cased characters in the string are uppercase and there is at
    least one cased character, false otherwise.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.join(seq)
+.. method:: str.join(seq)
 
    Return a string which is the concatenation of the strings in the sequence *seq*.
    The separator between elements is the string providing this method.
 
 
-.. method:: string.ljust(width[, fillchar])
+.. method:: str.ljust(width[, fillchar])
 
    Return the string left justified in a string of length *width*. Padding is done
    using the specified *fillchar* (default is a space).  The original string is
    returned if *width* is less than ``len(s)``.
 
    .. versionchanged:: 2.4
       Support for the *fillchar* argument.
 
 
-.. method:: string.lower()
+.. method:: str.lower()
 
    Return a copy of the string converted to lowercase.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.lstrip([chars])
+.. method:: str.lstrip([chars])
 
    Return a copy of the string with leading characters removed.  The *chars*
    argument is a string specifying the set of characters to be removed.  If omitted
    or ``None``, the *chars* argument defaults to removing whitespace.  The *chars*
-   argument is not a prefix; rather, all combinations of its values are stripped::
+   argument is not a prefix; rather, all combinations of its values are stripped:
 
       >>> '   spacious   '.lstrip()
       'spacious   '
       >>> 'www.example.com'.lstrip('cmowz.')
       'example.com'
 
    .. versionchanged:: 2.2.2
       Support for the *chars* argument.
 
 
-.. method:: string.partition(sep)
+.. method:: str.partition(sep)
 
    Split the string at the first occurrence of *sep*, and return a 3-tuple
    containing the part before the separator, the separator itself, and the part
    after the separator.  If the separator is not found, return a 3-tuple containing
    the string itself, followed by two empty strings.
 
    .. versionadded:: 2.5
 
 
-.. method:: string.replace(old, new[, count])
+.. method:: str.replace(old, new[, count])
 
    Return a copy of the string with all occurrences of substring *old* replaced by
    *new*.  If the optional argument *count* is given, only the first *count*
    occurrences are replaced.
 
 
-.. method:: string.rfind(sub [,start [,end]])
+.. method:: str.rfind(sub [,start [,end]])
 
    Return the highest index in the string where substring *sub* is found, such that
    *sub* is contained within s[start,end].  Optional arguments *start* and *end*
    are interpreted as in slice notation.  Return ``-1`` on failure.
 
 
-.. method:: string.rindex(sub[, start[, end]])
+.. method:: str.rindex(sub[, start[, end]])
 
    Like :meth:`rfind` but raises :exc:`ValueError` when the substring *sub* is not
    found.
 
 
-.. method:: string.rjust(width[, fillchar])
+.. method:: str.rjust(width[, fillchar])
 
    Return the string right justified in a string of length *width*. Padding is done
    using the specified *fillchar* (default is a space). The original string is
    returned if *width* is less than ``len(s)``.
 
    .. versionchanged:: 2.4
       Support for the *fillchar* argument.
 
 
-.. method:: string.rpartition(sep)
+.. method:: str.rpartition(sep)
 
    Split the string at the last occurrence of *sep*, and return a 3-tuple
    containing the part before the separator, the separator itself, and the part
    after the separator.  If the separator is not found, return a 3-tuple containing
    two empty strings, followed by the string itself.
 
    .. versionadded:: 2.5
 
 
-.. method:: string.rsplit([sep [,maxsplit]])
+.. method:: str.rsplit([sep [,maxsplit]])
 
    Return a list of the words in the string, using *sep* as the delimiter string.
    If *maxsplit* is given, at most *maxsplit* splits are done, the *rightmost*
    ones.  If *sep* is not specified or ``None``, any whitespace string is a
    separator.  Except for splitting from the right, :meth:`rsplit` behaves like
    :meth:`split` which is described in detail below.
 
    .. versionadded:: 2.4
 
 
-.. method:: string.rstrip([chars])
+.. method:: str.rstrip([chars])
 
    Return a copy of the string with trailing characters removed.  The *chars*
    argument is a string specifying the set of characters to be removed.  If omitted
    or ``None``, the *chars* argument defaults to removing whitespace.  The *chars*
-   argument is not a suffix; rather, all combinations of its values are stripped::
+   argument is not a suffix; rather, all combinations of its values are stripped:
 
       >>> '   spacious   '.rstrip()
       '   spacious'
       >>> 'mississippi'.rstrip('ipz')
       'mississ'
 
    .. versionchanged:: 2.2.2
       Support for the *chars* argument.
 
 
-.. method:: string.split([sep [,maxsplit]])
+.. method:: str.split([sep[, maxsplit]])
 
-   Return a list of the words in the string, using *sep* as the delimiter string.
-   If *maxsplit* is given, at most *maxsplit* splits are done. (thus, the list will
-   have at most ``maxsplit+1`` elements).  If *maxsplit* is not specified, then
-   there is no limit on the number of splits (all possible splits are made).
-   Consecutive delimiters are not grouped together and are deemed to delimit empty
-   strings (for example, ``'1,,2'.split(',')`` returns ``['1', '', '2']``).  The
-   *sep* argument may consist of multiple characters (for example, ``'1, 2,
-   3'.split(', ')`` returns ``['1', '2', '3']``).  Splitting an empty string with a
-   specified separator returns ``['']``.
+   Return a list of the words in the string, using *sep* as the delimiter
+   string.  If *maxsplit* is given, at most *maxsplit* splits are done (thus,
+   the list will have at most ``maxsplit+1`` elements).  If *maxsplit* is not
+   specified, then there is no limit on the number of splits (all possible
+   splits are made).
+
+   If *sep* is given, consecutive delimiters are not grouped together and are
+   deemed to delimit empty strings (for example, ``'1,,2'.split(',')`` returns
+   ``['1', '', '2']``).  The *sep* argument may consist of multiple characters
+   (for example, ``'1<>2<>3'.split('<>')`` returns ``['1', '2', '3']``).
+   Splitting an empty string with a specified separator returns ``['']``.
 
    If *sep* is not specified or is ``None``, a different splitting algorithm is
-   applied.  First, whitespace characters (spaces, tabs, newlines, returns, and
-   formfeeds) are stripped from both ends.  Then, words are separated by arbitrary
-   length strings of whitespace characters. Consecutive whitespace delimiters are
-   treated as a single delimiter (``'1  2  3'.split()`` returns ``['1', '2',
-   '3']``). Splitting an empty string or a string consisting of just whitespace
-   returns an empty list.
+   applied: runs of consecutive whitespace are regarded as a single separator,
+   and the result will contain no empty strings at the start or end if the
+   string has leading or trailing whitespace.  Consequently, splitting an empty
+   string or a string consisting of just whitespace with a ``None`` separator
+   returns ``[]``.
+
+   For example, ``' 1  2   3  '.split()`` returns ``['1', '2', '3']``, and
+   ``'  1  2   3  '.split(None, 1)`` returns ``['1', '2   3  ']``.
 
 
-.. method:: string.splitlines([keepends])
+.. method:: str.splitlines([keepends])
 
    Return a list of the lines in the string, breaking at line boundaries.  Line
    breaks are not included in the resulting list unless *keepends* is given and
    true.
 
 
-.. method:: string.startswith(prefix[, start[, end]])
+.. method:: str.startswith(prefix[, start[, end]])
 
    Return ``True`` if string starts with the *prefix*, otherwise return ``False``.
-   *prefix* can also be a tuple of suffixes to look for.  With optional *start*,
+   *prefix* can also be a tuple of prefixes to look for.  With optional *start*,
    test string beginning at that position.  With optional *end*, stop comparing
    string at that position.
 
    .. versionchanged:: 2.5
       Accept tuples as *prefix*.
 
 
-.. method:: string.strip([chars])
+.. method:: str.strip([chars])
 
    Return a copy of the string with the leading and trailing characters removed.
    The *chars* argument is a string specifying the set of characters to be removed.
    If omitted or ``None``, the *chars* argument defaults to removing whitespace.
    The *chars* argument is not a prefix or suffix; rather, all combinations of its
-   values are stripped::
+   values are stripped:
 
       >>> '   spacious   '.strip()
       'spacious'
       >>> 'www.example.com'.strip('cmowz.')
       'example'
 
    .. versionchanged:: 2.2.2
       Support for the *chars* argument.
 
 
-.. method:: string.swapcase()
+.. method:: str.swapcase()
 
    Return a copy of the string with uppercase characters converted to lowercase and
    vice versa.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.title()
+.. method:: str.title()
 
    Return a titlecased version of the string: words start with uppercase
    characters, all remaining cased characters are lowercase.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.translate(table[, deletechars])
+.. method:: str.translate(table[, deletechars])
 
    Return a copy of the string where all characters occurring in the optional
    argument *deletechars* are removed, and the remaining characters have been
    mapped through the given translation table, which must be a string of length
    256.
 
+   You can use the :func:`maketrans` helper function in the :mod:`string` module to
+   create a translation table. For string objects, set the *table* argument to
+   ``None`` for translations that only delete characters:
+
+      >>> 'read this short text'.translate(None, 'aeiou')
+      'rd ths shrt txt'
+
+   .. versionadded:: 2.6
+      Support for a ``None`` *table* argument.
+
    For Unicode objects, the :meth:`translate` method does not accept the optional
    *deletechars* argument.  Instead, it returns a copy of the *s* where all
    characters have been mapped through the given translation table which must be a
    mapping of Unicode ordinals to Unicode ordinals, Unicode strings or ``None``.
    Unmapped characters are left untouched. Characters mapped to ``None`` are
    deleted.  Note, a more flexible approach is to create a custom character mapping
    codec using the :mod:`codecs` module (see :mod:`encodings.cp1251` for an
    example).
 
 
-.. method:: string.upper()
+.. method:: str.upper()
 
    Return a copy of the string converted to uppercase.
 
    For 8-bit strings, this method is locale-dependent.
 
 
-.. method:: string.zfill(width)
+.. method:: str.zfill(width)
+
+   Return the numeric string left filled with zeros in a string of length
+   *width*.  A sign prefix is handled correctly.  The original string is
+   returned if *width* is less than ``len(s)``.
 
-   Return the numeric string left filled with zeros in a string of length *width*.
-   The original string is returned if *width* is less than ``len(s)``.
 
    .. versionadded:: 2.2.2
 
+The following methods are present only on unicode objects:
+
+.. method:: unicode.isnumeric()
+
+   Return ``True`` if there are only numeric characters in S, ``False``
+   otherwise. Numeric characters include digit characters, and all characters
+   that have the Unicode numeric value property, e.g. U+2155,
+   VULGAR FRACTION ONE FIFTH.
+
+.. method:: unicode.isdecimal()
+
+   Return ``True`` if there are only decimal characters in S, ``False``
+   otherwise. Decimal characters include digit characters, and all characters
+   that that can be used to form decimal-radix numbers, e.g. U+0660,
+   ARABIC-INDIC DIGIT ZERO.
 
-.. _typesseq-strings:
+
+.. _string-formatting:
 
 String Formatting Operations
 ----------------------------
 
 .. index::
    single: formatting, string (%)
    single: interpolation, string (%)
    single: string; formatting
    single: string; interpolation
    single: printf-style formatting
    single: sprintf-style formatting
    single: % formatting
@@ -1064,122 +1244,108 @@
 #. Precision (optional), given as a ``'.'`` (dot) followed by the precision.  If
    specified as ``'*'`` (an asterisk), the actual width is read from the next
    element of the tuple in *values*, and the value to convert comes after the
    precision.
 
 #. Length modifier (optional).
 
 #. Conversion type.
 
 When the right argument is a dictionary (or other mapping type), then the
 formats in the string *must* include a parenthesised mapping key into that
 dictionary inserted immediately after the ``'%'`` character. The mapping key
-selects the value to be formatted from the mapping.  For example::
+selects the value to be formatted from the mapping.  For example:
 
    >>> print '%(language)s has %(#)03d quote types.' % \
-             {'language': "Python", "#": 2}
+   ...       {'language': "Python", "#": 2}
    Python has 002 quote types.
 
 In this case no ``*`` specifiers may occur in a format (since they require a
 sequential parameter list).
 
 The conversion flag characters are:
 
-+---------+-----------------------------------------------+
-| Flag    | Meaning                                       |
-+=========+===============================================+
-| ``'#'`` | The value conversion will use the "alternate  |
-|         | form" (where defined below).                  |
-+---------+-----------------------------------------------+
-| ``'0'`` | The conversion will be zero padded for        |
-|         | numeric values.                               |
-+---------+-----------------------------------------------+
-| ``'-'`` | The converted value is left adjusted          |
-|         | (overrides the ``'0'`` conversion if both are |
-|         | given).                                       |
-+---------+-----------------------------------------------+
-| ``' '`` | (a space) A blank should be left before a     |
-|         | positive number (or empty string) produced by |
-|         | a signed conversion.                          |
-+---------+-----------------------------------------------+
-| ``'+'`` | A sign character (``'+'`` or ``'-'``) will    |
-|         | precede the conversion (overrides a "space"   |
-|         | flag).                                        |
-+---------+-----------------------------------------------+
++---------+---------------------------------------------------------------------+
+| Flag    | Meaning                                                             |
++=========+=====================================================================+
+| ``'#'`` | The value conversion will use the "alternate form" (where defined   |
+|         | below).                                                             |
++---------+---------------------------------------------------------------------+
+| ``'0'`` | The conversion will be zero padded for numeric values.              |
++---------+---------------------------------------------------------------------+
+| ``'-'`` | The converted value is left adjusted (overrides the ``'0'``         |
+|         | conversion if both are given).                                      |
++---------+---------------------------------------------------------------------+
+| ``' '`` | (a space) A blank should be left before a positive number (or empty |
+|         | string) produced by a signed conversion.                            |
++---------+---------------------------------------------------------------------+
+| ``'+'`` | A sign character (``'+'`` or ``'-'``) will precede the conversion   |
+|         | (overrides a "space" flag).                                         |
++---------+---------------------------------------------------------------------+
 
 A length modifier (``h``, ``l``, or ``L``) may be present, but is ignored as it
-is not necessary for Python.
+is not necessary for Python -- so e.g. ``%ld`` is identical to ``%d``.
 
 The conversion types are:
 
-+------------+---------------------------------+-------+
-| Conversion | Meaning                         | Notes |
-+============+=================================+=======+
-| ``'d'``    | Signed integer decimal.         |       |
-+------------+---------------------------------+-------+
-| ``'i'``    | Signed integer decimal.         |       |
-+------------+---------------------------------+-------+
-| ``'o'``    | Unsigned octal.                 | \(1)  |
-+------------+---------------------------------+-------+
-| ``'u'``    | Unsigned decimal.               |       |
-+------------+---------------------------------+-------+
-| ``'x'``    | Unsigned hexadecimal            | \(2)  |
-|            | (lowercase).                    |       |
-+------------+---------------------------------+-------+
-| ``'X'``    | Unsigned hexadecimal            | \(2)  |
-|            | (uppercase).                    |       |
-+------------+---------------------------------+-------+
-| ``'e'``    | Floating point exponential      | \(3)  |
-|            | format (lowercase).             |       |
-+------------+---------------------------------+-------+
-| ``'E'``    | Floating point exponential      | \(3)  |
-|            | format (uppercase).             |       |
-+------------+---------------------------------+-------+
-| ``'f'``    | Floating point decimal format.  | \(3)  |
-+------------+---------------------------------+-------+
-| ``'F'``    | Floating point decimal format.  | \(3)  |
-+------------+---------------------------------+-------+
-| ``'g'``    | Floating point format. Uses     | \(4)  |
-|            | exponential format if exponent  |       |
-|            | is greater than -4 or less than |       |
-|            | precision, decimal format       |       |
-|            | otherwise.                      |       |
-+------------+---------------------------------+-------+
-| ``'G'``    | Floating point format. Uses     | \(4)  |
-|            | exponential format if exponent  |       |
-|            | is greater than -4 or less than |       |
-|            | precision, decimal format       |       |
-|            | otherwise.                      |       |
-+------------+---------------------------------+-------+
-| ``'c'``    | Single character (accepts       |       |
-|            | integer or single character     |       |
-|            | string).                        |       |
-+------------+---------------------------------+-------+
-| ``'r'``    | String (converts any python     | \(5)  |
-|            | object using :func:`repr`).     |       |
-+------------+---------------------------------+-------+
-| ``'s'``    | String (converts any python     | \(6)  |
-|            | object using :func:`str`).      |       |
-+------------+---------------------------------+-------+
-| ``'%'``    | No argument is converted,       |       |
-|            | results in a ``'%'`` character  |       |
-|            | in the result.                  |       |
-+------------+---------------------------------+-------+
++------------+-----------------------------------------------------+-------+
+| Conversion | Meaning                                             | Notes |
++============+=====================================================+=======+
+| ``'d'``    | Signed integer decimal.                             |       |
++------------+-----------------------------------------------------+-------+
+| ``'i'``    | Signed integer decimal.                             |       |
++------------+-----------------------------------------------------+-------+
+| ``'o'``    | Signed octal value.                                 | \(1)  |
++------------+-----------------------------------------------------+-------+
+| ``'u'``    | Obsolete type -- it is identical to ``'d'``.        | \(7)  |
++------------+-----------------------------------------------------+-------+
+| ``'x'``    | Signed hexadecimal (lowercase).                     | \(2)  |
++------------+-----------------------------------------------------+-------+
+| ``'X'``    | Signed hexadecimal (uppercase).                     | \(2)  |
++------------+-----------------------------------------------------+-------+
+| ``'e'``    | Floating point exponential format (lowercase).      | \(3)  |
++------------+-----------------------------------------------------+-------+
+| ``'E'``    | Floating point exponential format (uppercase).      | \(3)  |
++------------+-----------------------------------------------------+-------+
+| ``'f'``    | Floating point decimal format.                      | \(3)  |
++------------+-----------------------------------------------------+-------+
+| ``'F'``    | Floating point decimal format.                      | \(3)  |
++------------+-----------------------------------------------------+-------+
+| ``'g'``    | Floating point format. Uses lowercase exponential   | \(4)  |
+|            | format if exponent is less than -4 or not less than |       |
+|            | precision, decimal format otherwise.                |       |
++------------+-----------------------------------------------------+-------+
+| ``'G'``    | Floating point format. Uses uppercase exponential   | \(4)  |
+|            | format if exponent is less than -4 or not less than |       |
+|            | precision, decimal format otherwise.                |       |
++------------+-----------------------------------------------------+-------+
+| ``'c'``    | Single character (accepts integer or single         |       |
+|            | character string).                                  |       |
++------------+-----------------------------------------------------+-------+
+| ``'r'``    | String (converts any python object using            | \(5)  |
+|            | :func:`repr`).                                      |       |
++------------+-----------------------------------------------------+-------+
+| ``'s'``    | String (converts any python object using            | \(6)  |
+|            | :func:`str`).                                       |       |
++------------+-----------------------------------------------------+-------+
+| ``'%'``    | No argument is converted, results in a ``'%'``      |       |
+|            | character in the result.                            |       |
++------------+-----------------------------------------------------+-------+
 
 Notes:
 
 (1)
-   The alternate form causes a leading zero (``'0'``) to be inserted between left-
-   hand padding and the formatting of the number if the leading character of the
-   result is not already a zero.
+   The alternate form causes a leading zero (``'0'``) to be inserted between
+   left-hand padding and the formatting of the number if the leading character
+   of the result is not already a zero.
 
 (2)
    The alternate form causes a leading ``'0x'`` or ``'0X'`` (depending on whether
    the ``'x'`` or ``'X'`` format was used) to be inserted between left-hand padding
    and the formatting of the number if the leading character of the result is not
    already a zero.
 
 (3)
    The alternate form causes the result to always contain a decimal point, even if
    no digits follow it.
 
    The precision determines the number of digits after the decimal point and
@@ -1194,31 +1360,34 @@
 
 (5)
    The ``%r`` conversion was added in Python 2.0.
 
    The precision determines the maximal number of characters used.
 
 (6)
    If the object or format provided is a :class:`unicode` string, the resulting
    string will also be :class:`unicode`.
 
    The precision determines the maximal number of characters used.
 
+(7)
+   See :pep:`237`.
+
 Since Python strings have an explicit length, ``%s`` conversions do not assume
 that ``'\0'`` is the end of the string.
 
-.. % XXX Examples?
+.. XXX Examples?
 
 For safety reasons, floating point precisions are clipped to 50; ``%f``
-conversions for numbers whose absolute value is over 1e25 are replaced by ``%g``
+conversions for numbers whose absolute value is over 1e50 are replaced by ``%g``
 conversions. [#]_  All other errors raise exceptions.
 
 .. index::
    module: string
    module: re
 
 Additional string operations are defined in standard modules :mod:`string` and
 :mod:`re`.
 
 
 .. _typesseq-xrange:
 
@@ -1269,44 +1438,43 @@
 | ``del s[i:j:k]``             | removes the elements of        |                     |
 |                              | ``s[i:j:k]`` from the list     |                     |
 +------------------------------+--------------------------------+---------------------+
 | ``s.append(x)``              | same as ``s[len(s):len(s)] =   | \(2)                |
 |                              | [x]``                          |                     |
 +------------------------------+--------------------------------+---------------------+
 | ``s.extend(x)``              | same as ``s[len(s):len(s)] =   | \(3)                |
 |                              | x``                            |                     |
 +------------------------------+--------------------------------+---------------------+
 | ``s.count(x)``               | return number of *i*'s for     |                     |
 |                              | which ``s[i] == x``            |                     |
 +------------------------------+--------------------------------+---------------------+
-| ``s.index(x[, *i*[, *j*]])`` | return smallest *k* such that  | \(4)                |
+| ``s.index(x[, i[, j]])``     | return smallest *k* such that  | \(4)                |
 |                              | ``s[k] == x`` and ``i <= k <   |                     |
 |                              | j``                            |                     |
 +------------------------------+--------------------------------+---------------------+
 | ``s.insert(i, x)``           | same as ``s[i:i] = [x]``       | \(5)                |
 +------------------------------+--------------------------------+---------------------+
-| ``s.pop([*i*])``             | same as ``x = s[i]; del s[i];  | \(6)                |
+| ``s.pop([i])``               | same as ``x = s[i]; del s[i];  | \(6)                |
 |                              | return x``                     |                     |
 +------------------------------+--------------------------------+---------------------+
 | ``s.remove(x)``              | same as ``del s[s.index(x)]``  | \(4)                |
 +------------------------------+--------------------------------+---------------------+
 | ``s.reverse()``              | reverses the items of *s* in   | \(7)                |
 |                              | place                          |                     |
 +------------------------------+--------------------------------+---------------------+
-| ``s.sort([*cmp*[, *key*[,    | sort the items of *s* in place | (7), (8), (9), (10) |
-| *reverse*]]])``              |                                |                     |
+| ``s.sort([cmp[, key[,        | sort the items of *s* in place | (7)(8)(9)(10)       |
+| reverse]]])``                |                                |                     |
 +------------------------------+--------------------------------+---------------------+
 
 .. index::
-   quadruple: operations on; mutable; sequence; types
    triple: operations on; sequence; types
    triple: operations on; list; type
    pair: subscript; assignment
    pair: slice; assignment
    pair: extended slice; assignment
    statement: del
    single: append() (list method)
    single: extend() (list method)
    single: count() (list method)
    single: index() (list method)
    single: insert() (list method)
    single: pop() (list method)
@@ -1353,28 +1521,29 @@
 (7)
    The :meth:`sort` and :meth:`reverse` methods modify the list in place for
    economy of space when sorting or reversing a large list.  To remind you that
    they operate by side effect, they don't return the sorted or reversed list.
 
 (8)
    The :meth:`sort` method takes optional arguments for controlling the
    comparisons.
 
    *cmp* specifies a custom comparison function of two arguments (list items) which
    should return a negative, zero or positive number depending on whether the first
    argument is considered smaller than, equal to, or larger than the second
-   argument: ``cmp=lambda x,y: cmp(x.lower(), y.lower())``
+   argument: ``cmp=lambda x,y: cmp(x.lower(), y.lower())``.  The default value
+   is ``None``.
 
    *key* specifies a function of one argument that is used to extract a comparison
-   key from each list element: ``key=str.lower``
+   key from each list element: ``key=str.lower``.  The default value is ``None``.
 
    *reverse* is a boolean value.  If set to ``True``, then the list elements are
    sorted as if each comparison were reversed.
 
    In general, the *key* and *reverse* conversion processes are much faster than
    specifying an equivalent *cmp* function.  This is because *cmp* is called
    multiple times for each list element while *key* and *reverse* touch each
    element only once.
 
    .. versionchanged:: 2.3
       Support for ``None`` as an equivalent to omitting *cmp* was added.
 
@@ -1392,410 +1561,552 @@
    inspect, the list is undefined.  The C implementation of Python 2.3 and newer
    makes the list appear empty for the duration, and raises :exc:`ValueError` if it
    can detect that the list has been mutated during a sort.
 
 
 .. _types-set:
 
 Set Types --- :class:`set`, :class:`frozenset`
 ==============================================
 
 .. index:: object: set
 
-A :dfn:`set` object is an unordered collection of immutable values. Common uses
-include membership testing, removing duplicates from a sequence, and computing
-mathematical operations such as intersection, union, difference, and symmetric
-difference.
+A :dfn:`set` object is an unordered collection of distinct :term:`hashable` objects.
+Common uses include membership testing, removing duplicates from a sequence, and
+computing mathematical operations such as intersection, union, difference, and
+symmetric difference.
+(For other containers see the built in :class:`dict`, :class:`list`,
+and :class:`tuple` classes, and the :mod:`collections` module.)
+
 
 .. versionadded:: 2.4
 
 Like other collections, sets support ``x in set``, ``len(set)``, and ``for x in
 set``.  Being an unordered collection, sets do not record element position or
 order of insertion.  Accordingly, sets do not support indexing, slicing, or
 other sequence-like behavior.
 
 There are currently two builtin set types, :class:`set` and :class:`frozenset`.
 The :class:`set` type is mutable --- the contents can be changed using methods
 like :meth:`add` and :meth:`remove`.  Since it is mutable, it has no hash value
 and cannot be used as either a dictionary key or as an element of another set.
-The :class:`frozenset` type is immutable and hashable --- its contents cannot be
-altered after is created; however, it can be used as a dictionary key or as an
-element of another set.
-
-Instances of :class:`set` and :class:`frozenset` provide the following
-operations:
-
-+-------------------------------+------------+---------------------------------+
-| Operation                     | Equivalent | Result                          |
-+===============================+============+=================================+
-| ``len(s)``                    |            | cardinality of set *s*          |
-+-------------------------------+------------+---------------------------------+
-| ``x in s``                    |            | test *x* for membership in *s*  |
-+-------------------------------+------------+---------------------------------+
-| ``x not in s``                |            | test *x* for non-membership in  |
-|                               |            | *s*                             |
-+-------------------------------+------------+---------------------------------+
-| ``s.issubset(t)``             | ``s <= t`` | test whether every element in   |
-|                               |            | *s* is in *t*                   |
-+-------------------------------+------------+---------------------------------+
-| ``s.issuperset(t)``           | ``s >= t`` | test whether every element in   |
-|                               |            | *t* is in *s*                   |
-+-------------------------------+------------+---------------------------------+
-| ``s.union(t)``                | *s* \| *t* | new set with elements from both |
-|                               |            | *s* and *t*                     |
-+-------------------------------+------------+---------------------------------+
-| ``s.intersection(t)``         | *s* & *t*  | new set with elements common to |
-|                               |            | *s* and *t*                     |
-+-------------------------------+------------+---------------------------------+
-| ``s.difference(t)``           | *s* - *t*  | new set with elements in *s*    |
-|                               |            | but not in *t*                  |
-+-------------------------------+------------+---------------------------------+
-| ``s.symmetric_difference(t)`` | *s* ^ *t*  | new set with elements in either |
-|                               |            | *s* or *t* but not both         |
-+-------------------------------+------------+---------------------------------+
-| ``s.copy()``                  |            | new set with a shallow copy of  |
-|                               |            | *s*                             |
-+-------------------------------+------------+---------------------------------+
-
-Note, the non-operator versions of :meth:`union`, :meth:`intersection`,
-:meth:`difference`, and :meth:`symmetric_difference`, :meth:`issubset`, and
-:meth:`issuperset` methods will accept any iterable as an argument.  In
-contrast, their operator based counterparts require their arguments to be sets.
-This precludes error-prone constructions like ``set('abc') & 'cbs'`` in favor of
-the more readable ``set('abc').intersection('cbs')``.
-
-Both :class:`set` and :class:`frozenset` support set to set comparisons. Two
-sets are equal if and only if every element of each set is contained in the
-other (each is a subset of the other). A set is less than another set if and
-only if the first set is a proper subset of the second set (is a subset, but is
-not equal). A set is greater than another set if and only if the first set is a
-proper superset of the second set (is a superset, but is not equal).
-
-Instances of :class:`set` are compared to instances of :class:`frozenset` based
-on their members.  For example, ``set('abc') == frozenset('abc')`` returns
-``True``.
-
-The subset and equality comparisons do not generalize to a complete ordering
-function.  For example, any two disjoint sets are not equal and are not subsets
-of each other, so *all* of the following return ``False``:  ``a<b``, ``a==b``,
-or ``a>b``. Accordingly, sets do not implement the :meth:`__cmp__` method.
-
-Since sets only define partial ordering (subset relationships), the output of
-the :meth:`list.sort` method is undefined for lists of sets.
-
-Set elements are like dictionary keys; they need to define both :meth:`__hash__`
-and :meth:`__eq__` methods.
-
-Binary operations that mix :class:`set` instances with :class:`frozenset` return
-the type of the first operand.  For example: ``frozenset('ab') | set('bc')``
-returns an instance of :class:`frozenset`.
-
-The following table lists operations available for :class:`set` that do not
-apply to immutable instances of :class:`frozenset`:
-
-+--------------------------------------+-------------+---------------------------------+
-| Operation                            | Equivalent  | Result                          |
-+======================================+=============+=================================+
-| ``s.update(t)``                      | *s* \|= *t* | update set *s*, adding elements |
-|                                      |             | from *t*                        |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.intersection_update(t)``         | *s* &= *t*  | update set *s*, keeping only    |
-|                                      |             | elements found in both *s* and  |
-|                                      |             | *t*                             |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.difference_update(t)``           | *s* -= *t*  | update set *s*, removing        |
-|                                      |             | elements found in *t*           |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.symmetric_difference_update(t)`` | *s* ^= *t*  | update set *s*, keeping only    |
-|                                      |             | elements found in either *s* or |
-|                                      |             | *t* but not in both             |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.add(x)``                         |             | add element *x* to set *s*      |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.remove(x)``                      |             | remove *x* from set *s*; raises |
-|                                      |             | :exc:`KeyError` if not present  |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.discard(x)``                     |             | removes *x* from set *s* if     |
-|                                      |             | present                         |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.pop()``                          |             | remove and return an arbitrary  |
-|                                      |             | element from *s*; raises        |
-|                                      |             | :exc:`KeyError` if empty        |
-+--------------------------------------+-------------+---------------------------------+
-| ``s.clear()``                        |             | remove all elements from set    |
-|                                      |             | *s*                             |
-+--------------------------------------+-------------+---------------------------------+
-
-Note, the non-operator versions of the :meth:`update`,
-:meth:`intersection_update`, :meth:`difference_update`, and
-:meth:`symmetric_difference_update` methods will accept any iterable as an
-argument.
+The :class:`frozenset` type is immutable and :term:`hashable` --- its contents cannot be
+altered after it is created; it can therefore be used as a dictionary key or as
+an element of another set.
+
+The constructors for both classes work the same:
+
+.. class:: set([iterable])
+           frozenset([iterable])
+
+   Return a new set or frozenset object whose elements are taken from
+   *iterable*.  The elements of a set must be hashable.  To represent sets of
+   sets, the inner sets must be :class:`frozenset` objects.  If *iterable* is
+   not specified, a new empty set is returned.
+
+   Instances of :class:`set` and :class:`frozenset` provide the following
+   operations:
+
+   .. describe:: len(s)
+
+      Return the cardinality of set *s*.
+
+   .. describe:: x in s
+
+      Test *x* for membership in *s*.
+
+   .. describe:: x not in s
+
+      Test *x* for non-membership in *s*.
+
+   .. method:: isdisjoint(other)
+
+      Return True if the set has no elements in common with *other*.  Sets are
+      disjoint if and only if their intersection is the empty set.
+
+      .. versionadded:: 2.6
+
+   .. method:: issubset(other)
+               set <= other
+
+      Test whether every element in the set is in *other*.
+
+   .. method:: set < other
+
+      Test whether the set is a true subset of *other*, that is,
+      ``set <= other and set != other``.
+
+   .. method:: issuperset(other)
+               set >= other
+
+      Test whether every element in *other* is in the set.
+
+   .. method:: set > other
+
+      Test whether the set is a true superset of *other*, that is, ``set >=
+      other and set != other``.
+
+   .. method:: union(other, ...)
+               set | other | ...
+
+      Return a new set with elements from the set and all others.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
+
+   .. method:: intersection(other, ...)
+               set & other & ...
+
+      Return a new set with elements common to the set and all others.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
+
+   .. method:: difference(other, ...)
+               set - other - ...
+
+      Return a new set with elements in the set that are not in the others.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
+
+   .. method:: symmetric_difference(other)
+               set ^ other
+
+      Return a new set with elements in either the set or *other* but not both.
+
+   .. method:: copy()
+
+      Return a new set with a shallow copy of *s*.
+
+
+   Note, the non-operator versions of :meth:`union`, :meth:`intersection`,
+   :meth:`difference`, and :meth:`symmetric_difference`, :meth:`issubset`, and
+   :meth:`issuperset` methods will accept any iterable as an argument.  In
+   contrast, their operator based counterparts require their arguments to be
+   sets.  This precludes error-prone constructions like ``set('abc') & 'cbs'``
+   in favor of the more readable ``set('abc').intersection('cbs')``.
+
+   Both :class:`set` and :class:`frozenset` support set to set comparisons. Two
+   sets are equal if and only if every element of each set is contained in the
+   other (each is a subset of the other). A set is less than another set if and
+   only if the first set is a proper subset of the second set (is a subset, but
+   is not equal). A set is greater than another set if and only if the first set
+   is a proper superset of the second set (is a superset, but is not equal).
+
+   Instances of :class:`set` are compared to instances of :class:`frozenset`
+   based on their members.  For example, ``set('abc') == frozenset('abc')``
+   returns ``True`` and so does ``set('abc') in set([frozenset('abc')])``.
+
+   The subset and equality comparisons do not generalize to a complete ordering
+   function.  For example, any two disjoint sets are not equal and are not
+   subsets of each other, so *all* of the following return ``False``: ``a<b``,
+   ``a==b``, or ``a>b``. Accordingly, sets do not implement the :meth:`__cmp__`
+   method.
+
+   Since sets only define partial ordering (subset relationships), the output of
+   the :meth:`list.sort` method is undefined for lists of sets.
+
+   Set elements, like dictionary keys, must be :term:`hashable`.
+
+   Binary operations that mix :class:`set` instances with :class:`frozenset`
+   return the type of the first operand.  For example: ``frozenset('ab') |
+   set('bc')`` returns an instance of :class:`frozenset`.
+
+   The following table lists operations available for :class:`set` that do not
+   apply to immutable instances of :class:`frozenset`:
+
+   .. method:: update(other, ...)
+               set |= other | ...
+
+      Update the set, adding elements from *other*.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
+
+   .. method:: intersection_update(other, ...)
+               set &= other & ...
+
+      Update the set, keeping only elements found in it and *other*.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
 
-The design of the set types was based on lessons learned from the :mod:`sets`
-module.
+   .. method:: difference_update(other, ...)
+               set -= other | ...
+
+      Update the set, removing elements found in others.
+
+      .. versionchanged:: 2.6
+         Accepts multiple input iterables.
+
+   .. method:: symmetric_difference_update(other)
+               set ^= other
+
+      Update the set, keeping only elements found in either set, but not in both.
+
+   .. method:: add(elem)
+
+      Add element *elem* to the set.
+
+   .. method:: remove(elem)
+
+      Remove element *elem* from the set.  Raises :exc:`KeyError` if *elem* is
+      not contained in the set.
+
+   .. method:: discard(elem)
+
+      Remove element *elem* from the set if it is present.
+
+   .. method:: pop()
+
+      Remove and return an arbitrary element from the set.  Raises
+      :exc:`KeyError` if the set is empty.
+
+   .. method:: clear()
+
+      Remove all elements from the set.
+
+
+   Note, the non-operator versions of the :meth:`update`,
+   :meth:`intersection_update`, :meth:`difference_update`, and
+   :meth:`symmetric_difference_update` methods will accept any iterable as an
+   argument.
+
+   Note, the *elem* argument to the :meth:`__contains__`, :meth:`remove`, and
+   :meth:`discard` methods may be a set.  To support searching for an equivalent
+   frozenset, the *elem* set is temporarily mutated during the search and then
+   restored.  During the search, the *elem* set should not be read or mutated
+   since it does not have a meaningful value.
 
 
 .. seealso::
 
-   `Comparison to the built-in set types <comparison-to-builtin-set.html>`_
+   :ref:`comparison-to-builtin-set`
       Differences between the :mod:`sets` module and the built-in set types.
 
 
 .. _typesmapping:
 
 Mapping Types --- :class:`dict`
 ===============================
 
 .. index::
    object: mapping
    object: dictionary
-
-A :dfn:`mapping` object maps  immutable values to arbitrary objects.  Mappings
-are mutable objects.  There is currently only one standard mapping type, the
-:dfn:`dictionary`.  A dictionary's keys are almost arbitrary values.  Only
-values containing lists, dictionaries or other mutable types (that are compared
-by value rather than by object identity) may not be used as keys. Numeric types
-used for keys obey the normal rules for numeric comparison: if two numbers
-compare equal (such as ``1`` and ``1.0``) then they can be used interchangeably
-to index the same dictionary entry.
-
-Dictionaries are created by placing a comma-separated list of ``key: value``
-pairs within braces, for example: ``{'jack': 4098, 'sjoerd': 4127}`` or ``{4098:
-'jack', 4127: 'sjoerd'}``.
-
-.. index::
    triple: operations on; mapping; types
    triple: operations on; dictionary; type
    statement: del
    builtin: len
-   single: clear() (dictionary method)
-   single: copy() (dictionary method)
-   single: has_key() (dictionary method)
-   single: fromkeys() (dictionary method)
-   single: items() (dictionary method)
-   single: keys() (dictionary method)
-   single: update() (dictionary method)
-   single: values() (dictionary method)
-   single: get() (dictionary method)
-   single: setdefault() (dictionary method)
-   single: pop() (dictionary method)
-   single: popitem() (dictionary method)
-   single: iteritems() (dictionary method)
-   single: iterkeys() (dictionary method)
-   single: itervalues() (dictionary method)
-
-The following operations are defined on mappings (where *a* and *b* are
-mappings, *k* is a key, and *v* and *x* are arbitrary objects):
-
-+--------------------------------+---------------------------------+-----------+
-| Operation                      | Result                          | Notes     |
-+================================+=================================+===========+
-| ``len(a)``                     | the number of items in *a*      |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a[k]``                       | the item of *a* with key *k*    | (1), (10) |
-+--------------------------------+---------------------------------+-----------+
-| ``a[k] = v``                   | set ``a[k]`` to *v*             |           |
-+--------------------------------+---------------------------------+-----------+
-| ``del a[k]``                   | remove ``a[k]`` from *a*        | \(1)      |
-+--------------------------------+---------------------------------+-----------+
-| ``a.clear()``                  | remove all items from ``a``     |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.copy()``                   | a (shallow) copy of ``a``       |           |
-+--------------------------------+---------------------------------+-----------+
-| ``k in a``                     | ``True`` if *a* has a key *k*,  | \(2)      |
-|                                | else ``False``                  |           |
-+--------------------------------+---------------------------------+-----------+
-| ``k not in a``                 | Equivalent to ``not`` *k* in    | \(2)      |
-|                                | *a*                             |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.has_key(k)``               | Equivalent to *k* ``in`` *a*,   |           |
-|                                | use that form in new code       |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.items()``                  | a copy of *a*'s list of (*key*, | \(3)      |
-|                                | *value*) pairs                  |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.keys()``                   | a copy of *a*'s list of keys    | \(3)      |
-+--------------------------------+---------------------------------+-----------+
-| ``a.update([*b*])``            | updates (and overwrites)        | \(9)      |
-|                                | key/value pairs from *b*        |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.fromkeys(seq[, *value*])`` | Creates a new dictionary with   | \(7)      |
-|                                | keys from *seq* and values set  |           |
-|                                | to *value*                      |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.values()``                 | a copy of *a*'s list of values  | \(3)      |
-+--------------------------------+---------------------------------+-----------+
-| ``a.get(k[, *x*])``            | ``a[k]`` if ``k in a``, else    | \(4)      |
-|                                | *x*                             |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.setdefault(k[, *x*])``     | ``a[k]`` if ``k in a``, else    | \(5)      |
-|                                | *x* (also setting it)           |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.pop(k[, *x*])``            | ``a[k]`` if ``k in a``, else    | \(8)      |
-|                                | *x* (and remove k)              |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.popitem()``                | remove and return an arbitrary  | \(6)      |
-|                                | (*key*, *value*) pair           |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.iteritems()``              | return an iterator over (*key*, | (2), (3)  |
-|                                | *value*) pairs                  |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.iterkeys()``               | return an iterator over the     | (2), (3)  |
-|                                | mapping's keys                  |           |
-+--------------------------------+---------------------------------+-----------+
-| ``a.itervalues()``             | return an iterator over the     | (2), (3)  |
-|                                | mapping's values                |           |
-+--------------------------------+---------------------------------+-----------+
 
-Notes:
+A :dfn:`mapping` object maps :term:`hashable` values to arbitrary objects.
+Mappings are mutable objects.  There is currently only one standard mapping
+type, the :dfn:`dictionary`.  (For other containers see the built in
+:class:`list`, :class:`set`, and :class:`tuple` classes, and the
+:mod:`collections` module.)
+
+A dictionary's keys are *almost* arbitrary values.  Values that are not
+:term:`hashable`, that is, values containing lists, dictionaries or other
+mutable types (that are compared by value rather than by object identity) may
+not be used as keys.  Numeric types used for keys obey the normal rules for
+numeric comparison: if two numbers compare equal (such as ``1`` and ``1.0``)
+then they can be used interchangeably to index the same dictionary entry.  (Note
+however, that since computers store floating-point numbers as approximations it
+is usually unwise to use them as dictionary keys.)
 
-(1)
-   Raises a :exc:`KeyError` exception if *k* is not in the map.
+Dictionaries can be created by placing a comma-separated list of ``key: value``
+pairs within braces, for example: ``{'jack': 4098, 'sjoerd': 4127}`` or ``{4098:
+'jack', 4127: 'sjoerd'}``, or by the :class:`dict` constructor.
+
+.. class:: dict([arg])
+
+   Return a new dictionary initialized from an optional positional argument or from
+   a set of keyword arguments. If no arguments are given, return a new empty
+   dictionary. If the positional argument *arg* is a mapping object, return a
+   dictionary mapping the same keys to the same values as does the mapping object.
+   Otherwise the positional argument must be a sequence, a container that supports
+   iteration, or an iterator object.  The elements of the argument must each also
+   be of one of those kinds, and each must in turn contain exactly two objects.
+   The first is used as a key in the new dictionary, and the second as the key's
+   value.  If a given key is seen more than once, the last value associated with it
+   is retained in the new dictionary.
+
+   If keyword arguments are given, the keywords themselves with their associated
+   values are added as items to the dictionary. If a key is specified both in the
+   positional argument and as a keyword argument, the value associated with the
+   keyword is retained in the dictionary. For example, these all return a
+   dictionary equal to ``{"one": 2, "two": 3}``:
+
+   * ``dict(one=2, two=3)``
+
+   * ``dict({'one': 2, 'two': 3})``
+
+   * ``dict(zip(('one', 'two'), (2, 3)))``
+
+   * ``dict([['two', 3], ['one', 2]])``
+
+   The first example only works for keys that are valid Python
+   identifiers; the others work with any valid keys.
 
-(2)
    .. versionadded:: 2.2
 
-(3)
-   Keys and values are listed in an arbitrary order which is non-random, varies
-   across Python implementations, and depends on the dictionary's history of
-   insertions and deletions. If :meth:`items`, :meth:`keys`, :meth:`values`,
-   :meth:`iteritems`, :meth:`iterkeys`, and :meth:`itervalues` are called with no
-   intervening modifications to the dictionary, the lists will directly correspond.
-   This allows the creation of ``(value, key)`` pairs using :func:`zip`: ``pairs =
-   zip(a.values(), a.keys())``.  The same relationship holds for the
-   :meth:`iterkeys` and :meth:`itervalues` methods: ``pairs = zip(a.itervalues(),
-   a.iterkeys())`` provides the same value for ``pairs``. Another way to create the
-   same list is ``pairs = [(v, k) for (k, v) in a.iteritems()]``.
+   .. versionchanged:: 2.3
+      Support for building a dictionary from keyword arguments added.
 
-(4)
-   Never raises an exception if *k* is not in the map, instead it returns *x*.  *x*
-   is optional; when *x* is not provided and *k* is not in the map, ``None`` is
-   returned.
 
-(5)
-   :func:`setdefault` is like :func:`get`, except that if *k* is missing, *x* is
-   both returned and inserted into the dictionary as the value of *k*. *x* defaults
-   to *None*.
+   These are the operations that dictionaries support (and therefore, custom
+   mapping types should support too):
 
-(6)
-   :func:`popitem` is useful to destructively iterate over a dictionary, as often
-   used in set algorithms.  If the dictionary is empty, calling :func:`popitem`
-   raises a :exc:`KeyError`.
+   .. describe:: len(d)
 
-(7)
-   :func:`fromkeys` is a class method that returns a new dictionary. *value*
-   defaults to ``None``.
+      Return the number of items in the dictionary *d*.
 
-   .. versionadded:: 2.3
+   .. describe:: d[key]
 
-(8)
-   :func:`pop` raises a :exc:`KeyError` when no default value is given and the key
-   is not found.
+      Return the item of *d* with key *key*.  Raises a :exc:`KeyError` if *key*
+      is not in the map.
 
-   .. versionadded:: 2.3
+      .. versionadded:: 2.5
+         If a subclass of dict defines a method :meth:`__missing__`, if the key
+         *key* is not present, the ``d[key]`` operation calls that method with
+         the key *key* as argument.  The ``d[key]`` operation then returns or
+         raises whatever is returned or raised by the ``__missing__(key)`` call
+         if the key is not present. No other operations or methods invoke
+         :meth:`__missing__`. If :meth:`__missing__` is not defined,
+         :exc:`KeyError` is raised.  :meth:`__missing__` must be a method; it
+         cannot be an instance variable. For an example, see
+         :class:`collections.defaultdict`.
 
-(9)
-   :func:`update` accepts either another mapping object or an iterable of key/value
-   pairs (as a tuple or other iterable of length two).  If keyword arguments are
-   specified, the mapping is then is updated with those key/value pairs:
-   ``d.update(red=1, blue=2)``.
+   .. describe:: d[key] = value
 
-   .. versionchanged:: 2.4
-      Allowed the argument to be an iterable of key/value pairs and allowed keyword
-      arguments.
+      Set ``d[key]`` to *value*.
 
-(10)
-   If a subclass of dict defines a method :meth:`__missing__`, if the key *k* is
-   not present, the *a*[*k*] operation calls that method with the key *k* as
-   argument.  The *a*[*k*] operation then returns or raises whatever is returned or
-   raised by the :func:`__missing__`\ (*k*) call if the key is not present. No
-   other operations or methods invoke :meth:`__missing__`\ (). If
-   :meth:`__missing__` is not defined, :exc:`KeyError` is raised.
-   :meth:`__missing__` must be a method; it cannot be an instance variable. For an
-   example, see :mod:`collections`.\ :class:`defaultdict`.
+   .. describe:: del d[key]
 
-   .. versionadded:: 2.5
+      Remove ``d[key]`` from *d*.  Raises a :exc:`KeyError` if *key* is not in the
+      map.
+
+   .. describe:: key in d
+
+      Return ``True`` if *d* has a key *key*, else ``False``.
+
+      .. versionadded:: 2.2
+
+   .. describe:: key not in d
+
+      Equivalent to ``not key in d``.
+
+      .. versionadded:: 2.2
+
+   .. describe:: iter(d)
+
+      Return an iterator over the keys of the dictionary.  This is a shortcut
+      for :meth:`iterkeys`.
+
+   .. method:: clear()
+
+      Remove all items from the dictionary.
+
+   .. method:: copy()
+
+      Return a shallow copy of the dictionary.
+
+   .. method:: fromkeys(seq[, value])
+
+      Create a new dictionary with keys from *seq* and values set to *value*.
+
+      :func:`fromkeys` is a class method that returns a new dictionary. *value*
+      defaults to ``None``.
+
+      .. versionadded:: 2.3
+
+   .. method:: get(key[, default])
+
+      Return the value for *key* if *key* is in the dictionary, else *default*.
+      If *default* is not given, it defaults to ``None``, so that this method
+      never raises a :exc:`KeyError`.
+
+   .. method:: has_key(key)
+
+      Test for the presence of *key* in the dictionary.  :meth:`has_key` is
+      deprecated in favor of ``key in d``.
+
+   .. method:: items()
+
+      Return a copy of the dictionary's list of ``(key, value)`` pairs.
+
+      .. note::
+
+         Keys and values are listed in an arbitrary order which is non-random,
+         varies across Python implementations, and depends on the dictionary's
+         history of insertions and deletions. If :meth:`items`, :meth:`keys`,
+         :meth:`values`, :meth:`iteritems`, :meth:`iterkeys`, and
+         :meth:`itervalues` are called with no intervening modifications to the
+         dictionary, the lists will directly correspond.  This allows the
+         creation of ``(value, key)`` pairs using :func:`zip`: ``pairs =
+         zip(d.values(), d.keys())``.  The same relationship holds for the
+         :meth:`iterkeys` and :meth:`itervalues` methods: ``pairs =
+         zip(d.itervalues(), d.iterkeys())`` provides the same value for
+         ``pairs``. Another way to create the same list is ``pairs = [(v, k) for
+         (k, v) in d.iteritems()]``.
+
+   .. method:: iteritems()
+
+      Return an iterator over the dictionary's ``(key, value)`` pairs.  See the
+      note for :meth:`dict.items`.
+
+      Using :meth:`iteritems` while adding or deleting entries in the dictionary
+      will raise a :exc:`RuntimeError`.
+
+      .. versionadded:: 2.2
+
+   .. method:: iterkeys()
+
+      Return an iterator over the dictionary's keys.  See the note for
+      :meth:`dict.items`.
+
+      Using :meth:`iterkeys` while adding or deleting entries in the dictionary
+      will raise a :exc:`RuntimeError`.
+
+      .. versionadded:: 2.2
+
+   .. method:: itervalues()
+
+      Return an iterator over the dictionary's values.  See the note for
+      :meth:`dict.items`.
+
+      Using :meth:`itervalues` while adding or deleting entries in the
+      dictionary will raise a :exc:`RuntimeError`.
+
+      .. versionadded:: 2.2
+
+   .. method:: keys()
+
+      Return a copy of the dictionary's list of keys.  See the note for
+      :meth:`dict.items`.
+
+   .. method:: pop(key[, default])
+
+      If *key* is in the dictionary, remove it and return its value, else return
+      *default*.  If *default* is not given and *key* is not in the dictionary,
+      a :exc:`KeyError` is raised.
+
+      .. versionadded:: 2.3
+
+   .. method:: popitem()
+
+      Remove and return an arbitrary ``(key, value)`` pair from the dictionary.
+
+      :func:`popitem` is useful to destructively iterate over a dictionary, as
+      often used in set algorithms.  If the dictionary is empty, calling
+      :func:`popitem` raises a :exc:`KeyError`.
+
+   .. method:: setdefault(key[, default])
+
+      If *key* is in the dictionary, return its value.  If not, insert *key*
+      with a value of *default* and return *default*.  *default* defaults to
+      ``None``.
+
+   .. method:: update([other])
+
+      Update the dictionary with the key/value pairs from *other*, overwriting
+      existing keys.  Return ``None``.
+
+      :func:`update` accepts either another dictionary object or an iterable of
+      key/value pairs (as a tuple or other iterable of length two).  If keyword
+      arguments are specified, the dictionary is then is updated with those
+      key/value pairs: ``d.update(red=1, blue=2)``.
+
+      .. versionchanged:: 2.4
+          Allowed the argument to be an iterable of key/value pairs and allowed
+          keyword arguments.
+
+   .. method:: values()
+
+      Return a copy of the dictionary's list of values.  See the note for
+      :meth:`dict.items`.
 
 
 .. _bltin-file-objects:
 
 File Objects
 ============
 
 .. index::
    object: file
    builtin: file
    module: os
    module: socket
 
-File objects are implemented using C's ``stdio`` package and can be created with
-the built-in constructor :func:`file` described in section
-:ref:`built-in-funcs`, "Built-in Functions." [#]_  File objects are also
-returned by some other built-in functions and methods, such as :func:`os.popen`
-and :func:`os.fdopen` and the :meth:`makefile` method of socket objects.
+File objects are implemented using C's ``stdio`` package and can be
+created with the built-in :func:`open` function.  File
+objects are also returned by some other built-in functions and methods,
+such as :func:`os.popen` and :func:`os.fdopen` and the :meth:`makefile`
+method of socket objects. Temporary files can be created using the
+:mod:`tempfile` module, and high-level file operations such as copying,
+moving, and deleting files and directories can be achieved with the
+:mod:`shutil` module.
 
 When a file operation fails for an I/O-related reason, the exception
 :exc:`IOError` is raised.  This includes situations where the operation is not
 defined for some reason, like :meth:`seek` on a tty device or writing a file
 opened for reading.
 
 Files have the following methods:
 
 
 .. method:: file.close()
 
    Close the file.  A closed file cannot be read or written any more. Any operation
    which requires that the file be open will raise a :exc:`ValueError` after the
    file has been closed.  Calling :meth:`close` more than once is allowed.
 
    As of Python 2.5, you can avoid having to call this method explicitly if you use
    the :keyword:`with` statement.  For example, the following code will
-   automatically close ``f`` when the :keyword:`with` block is exited::
+   automatically close *f* when the :keyword:`with` block is exited::
 
-      from __future__ import with_statement
+      from __future__ import with_statement # This isn't required in Python 2.6
 
       with open("hello.txt") as f:
           for line in f:
               print line
 
    In older versions of Python, you would have needed to do this to get the same
    effect::
 
       f = open("hello.txt")
       try:
           for line in f:
               print line
       finally:
           f.close()
 
    .. note::
 
       Not all "file-like" types in Python support use as a context manager for the
       :keyword:`with` statement.  If your code is intended to work with any file-like
-      object, you can use the :func:`closing` function in the :mod:`contextlib` module
-      instead of using the object directly.  See section :ref:`context-closing` for
-      details.
+      object, you can use the function :func:`contextlib.closing` instead of using
+      the object directly.
 
 
 .. method:: file.flush()
 
-   Flush the internal buffer, like ``stdio``'s :cfunc:`fflush`.  This may be a no-
-   op on some file-like objects.
+   Flush the internal buffer, like ``stdio``'s :cfunc:`fflush`.  This may be a
+   no-op on some file-like objects.
 
 
 .. method:: file.fileno()
 
    .. index::
-      single: file descriptor
-      single: descriptor, file
+      pair: file; descriptor
       module: fcntl
 
    Return the integer "file descriptor" that is used by the underlying
    implementation to request I/O operations from the operating system.  This can be
    useful for other, lower level interfaces that use file descriptors, such as the
    :mod:`fcntl` module or :func:`os.read` and friends.
 
    .. note::
 
       File-like objects which do not have a real file descriptor should *not* provide
       this method!
 
@@ -1807,97 +2118,112 @@
    .. note::
 
       If a file-like object is not associated with a real file, this method should
       *not* be implemented.
 
 
 .. method:: file.next()
 
    A file object is its own iterator, for example ``iter(f)`` returns *f* (unless
    *f* is closed).  When a file is used as an iterator, typically in a
    :keyword:`for` loop (for example, ``for line in f: print line``), the
    :meth:`next` method is called repeatedly.  This method returns the next input
-   line, or raises :exc:`StopIteration` when EOF is hit.  In order to make a
-   :keyword:`for` loop the most efficient way of looping over the lines of a file
-   (a very common operation), the :meth:`next` method uses a hidden read-ahead
+   line, or raises :exc:`StopIteration` when EOF is hit when the file is open for
+   reading (behavior is undefined when the file is open for writing).  In order to
+   make a :keyword:`for` loop the most efficient way of looping over the lines of a
+   file (a very common operation), the :meth:`next` method uses a hidden read-ahead
    buffer.  As a consequence of using a read-ahead buffer, combining :meth:`next`
    with other file methods (like :meth:`readline`) does not work right.  However,
    using :meth:`seek` to reposition the file to an absolute position will flush the
    read-ahead buffer.
 
    .. versionadded:: 2.3
 
 
 .. method:: file.read([size])
 
    Read at most *size* bytes from the file (less if the read hits EOF before
    obtaining *size* bytes).  If the *size* argument is negative or omitted, read
    all data until EOF is reached.  The bytes are returned as a string object.  An
    empty string is returned when EOF is encountered immediately.  (For certain
    files, like ttys, it makes sense to continue reading after an EOF is hit.)  Note
    that this method may call the underlying C function :cfunc:`fread` more than
    once in an effort to acquire as close to *size* bytes as possible. Also note
-   that when in non-blocking mode, less data than what was requested may be
+   that when in non-blocking mode, less data than was requested may be
    returned, even if no *size* parameter was given.
 
+   .. note::
+      This function is simply a wrapper for the underlying
+      :cfunc:`fread` C function, and will behave the same in corner cases,
+      such as whether the EOF value is cached.
+
 
 .. method:: file.readline([size])
 
    Read one entire line from the file.  A trailing newline character is kept in the
    string (but may be absent when a file ends with an incomplete line). [#]_  If
    the *size* argument is present and non-negative, it is a maximum byte count
    (including the trailing newline) and an incomplete line may be returned. An
    empty string is returned *only* when EOF is encountered immediately.
 
    .. note::
 
       Unlike ``stdio``'s :cfunc:`fgets`, the returned string contains null characters
       (``'\0'``) if they occurred in the input.
 
 
 .. method:: file.readlines([sizehint])
 
    Read until EOF using :meth:`readline` and return a list containing the lines
-   thus read.  If the optional *sizehint* argument is present, instead of reading
-   up to EOF, whole lines totalling approximately *sizehint* bytes (possibly after
-   rounding up to an internal buffer size) are read.  Objects implementing a file-
-   like interface may choose to ignore *sizehint* if it cannot be implemented, or
-   cannot be implemented efficiently.
+   thus read.  If the optional *sizehint* argument is present, instead of
+   reading up to EOF, whole lines totalling approximately *sizehint* bytes
+   (possibly after rounding up to an internal buffer size) are read.  Objects
+   implementing a file-like interface may choose to ignore *sizehint* if it
+   cannot be implemented, or cannot be implemented efficiently.
 
 
 .. method:: file.xreadlines()
 
    This method returns the same thing as ``iter(f)``.
 
    .. versionadded:: 2.1
 
    .. deprecated:: 2.3
       Use ``for line in file`` instead.
 
 
 .. method:: file.seek(offset[, whence])
 
    Set the file's current position, like ``stdio``'s :cfunc:`fseek`. The *whence*
-   argument is optional and defaults to ``0`` (absolute file positioning); other
-   values are ``1`` (seek relative to the current position) and ``2`` (seek
-   relative to the file's end).  There is no return value.  Note that if the file
-   is opened for appending (mode ``'a'`` or ``'a+'``), any :meth:`seek` operations
-   will be undone at the next write.  If the file is only opened for writing in
-   append mode (mode ``'a'``), this method is essentially a no-op, but it remains
-   useful for files opened in append mode with reading enabled (mode ``'a+'``).  If
-   the file is opened in text mode (without ``'b'``), only offsets returned by
-   :meth:`tell` are legal.  Use of other offsets causes undefined behavior.
+   argument is optional and defaults to  ``os.SEEK_SET`` or ``0`` (absolute file
+   positioning); other values are ``os.SEEK_CUR`` or ``1`` (seek relative to the
+   current position) and ``os.SEEK_END`` or ``2``  (seek relative to the file's
+   end).  There is no return value.
+
+   For example, ``f.seek(2, os.SEEK_CUR)`` advances the position by two and
+   ``f.seek(-3, os.SEEK_END)`` sets the position to the third to last.
+
+   Note that if the file is opened for appending
+   (mode ``'a'`` or ``'a+'``), any :meth:`seek` operations will be undone at the
+   next write.  If the file is only opened for writing in append mode (mode
+   ``'a'``), this method is essentially a no-op, but it remains useful for files
+   opened in append mode with reading enabled (mode ``'a+'``).  If the file is
+   opened in text mode (without ``'b'``), only offsets returned by :meth:`tell` are
+   legal.  Use of other offsets causes undefined behavior.
 
    Note that not all file objects are seekable.
 
+   .. versionchanged:: 2.6
+      Passing float values as offset has been deprecated.
+
 
 .. method:: file.tell()
 
    Return the file's current position, like ``stdio``'s :cfunc:`ftell`.
 
    .. note::
 
       On Windows, :meth:`tell` can return illegal values (after an :cfunc:`fgets`)
       when reading files with Unix-style line-endings. Use binary mode (``'rb'``) to
       circumvent this problem.
 
 
@@ -1946,37 +2272,44 @@
 
    The encoding that this file uses. When Unicode strings are written to a file,
    they will be converted to byte strings using this encoding. In addition, when
    the file is connected to a terminal, the attribute gives the encoding that the
    terminal is likely to use (that  information might be incorrect if the user has
    misconfigured the  terminal). The attribute is read-only and may not be present
    on all file-like objects. It may also be ``None``, in which case the file uses
    the system default encoding for converting Unicode strings.
 
    .. versionadded:: 2.3
 
 
+.. attribute:: file.errors
+
+   The Unicode error handler used along with the encoding.
+
+   .. versionadded:: 2.6
+
+
 .. attribute:: file.mode
 
    The I/O mode for the file.  If the file was created using the :func:`open`
    built-in function, this will be the value of the *mode* parameter.  This is a
    read-only attribute and may not be present on all file-like objects.
 
 
 .. attribute:: file.name
 
    If the file object was created using :func:`open`, the name of the file.
-   Otherwise, some string that indicates the source of the file object, of the form
-   ``<...>``.  This is a read-only attribute and may not be present on all file-
-   like objects.
+   Otherwise, some string that indicates the source of the file object, of the
+   form ``<...>``.  This is a read-only attribute and may not be present on all
+   file-like objects.
 
 
 .. attribute:: file.newlines
 
    If Python was built with the :option:`--with-universal-newlines` option to
    :program:`configure` (the default) this read-only attribute exists, and for
    files opened in universal newline read mode it keeps track of the types of
    newlines encountered while reading the file. The values it can take are
    ``'\r'``, ``'\n'``, ``'\r\n'``, ``None`` (unknown, no newlines read yet) or a
    tuple containing all the newline types seen, to indicate that multiple newline
    conventions were encountered. For files not opened in universal newline read
    mode the value of this attribute will be ``None``.
@@ -2011,70 +2344,71 @@
    single: context management protocol
    single: protocol; context management
 
 Python's :keyword:`with` statement supports the concept of a runtime context
 defined by a context manager.  This is implemented using two separate methods
 that allow user-defined classes to define a runtime context that is entered
 before the statement body is executed and exited when the statement ends.
 
 The :dfn:`context management protocol` consists of a pair of methods that need
 to be provided for a context manager object to define a runtime context:
 
 
-.. method:: context manager.__enter__()
+.. method:: contextmanager.__enter__()
 
    Enter the runtime context and return either this object or another object
    related to the runtime context. The value returned by this method is bound to
    the identifier in the :keyword:`as` clause of :keyword:`with` statements using
    this context manager.
 
    An example of a context manager that returns itself is a file object. File
    objects return themselves from __enter__() to allow :func:`open` to be used as
    the context expression in a :keyword:`with` statement.
 
    An example of a context manager that returns a related object is the one
-   returned by ``decimal.Context.get_manager()``. These managers set the active
+   returned by :func:`decimal.localcontext`. These managers set the active
    decimal context to a copy of the original decimal context and then return the
    copy. This allows changes to be made to the current decimal context in the body
    of the :keyword:`with` statement without affecting code outside the
    :keyword:`with` statement.
 
 
-.. method:: context manager.__exit__(exc_type, exc_val, exc_tb)
+.. method:: contextmanager.__exit__(exc_type, exc_val, exc_tb)
 
-   Exit the runtime context and return a Boolean flag indicating if any expection
+   Exit the runtime context and return a Boolean flag indicating if any exception
    that occurred should be suppressed. If an exception occurred while executing the
    body of the :keyword:`with` statement, the arguments contain the exception type,
-   value and traceback information. Otherwise, all three arguments are *None*.
+   value and traceback information. Otherwise, all three arguments are ``None``.
 
    Returning a true value from this method will cause the :keyword:`with` statement
    to suppress the exception and continue execution with the statement immediately
    following the :keyword:`with` statement. Otherwise the exception continues
    propagating after this method has finished executing. Exceptions that occur
    during execution of this method will replace any exception that occurred in the
    body of the :keyword:`with` statement.
 
    The exception passed in should never be reraised explicitly - instead, this
    method should return a false value to indicate that the method completed
    successfully and does not want to suppress the raised exception. This allows
    context management code (such as ``contextlib.nested``) to easily detect whether
    or not an :meth:`__exit__` method has actually failed.
 
 Python defines several context managers to support easy thread synchronisation,
 prompt closure of files or other objects, and simpler manipulation of the active
 decimal arithmetic context. The specific types are not treated specially beyond
-their implementation of the context management protocol.
+their implementation of the context management protocol. See the
+:mod:`contextlib` module for some examples.
 
-Python's generators and the ``contextlib.contextfactory`` decorator provide a
-convenient way to implement these protocols.  If a generator function is
+Python's :term:`generator`\s and the ``contextlib.contextfactory`` :term:`decorator`
+provide a convenient way to implement these protocols.  If a generator function is
 decorated with the ``contextlib.contextfactory`` decorator, it will return a
 context manager implementing the necessary :meth:`__enter__` and
 :meth:`__exit__` methods, rather than the iterator produced by an undecorated
 generator function.
 
 Note that there is no specific slot for any of these methods in the type
 structure for Python objects in the Python/C API. Extension types wanting to
 define these methods must provide them as a normal Python accessible method.
 Compared to the overhead of setting up the runtime context, the overhead of a
 single class dictionary lookup is negligible.
 
 
@@ -2099,52 +2433,48 @@
 foo`` does not require a module object named *foo* to exist, rather it requires
 an (external) *definition* for a module named *foo* somewhere.)
 
 A special member of every module is :attr:`__dict__`. This is the dictionary
 containing the module's symbol table. Modifying this dictionary will actually
 change the module's symbol table, but direct assignment to the :attr:`__dict__`
 attribute is not possible (you can write ``m.__dict__['a'] = 1``, which defines
 ``m.a`` to be ``1``, but you can't write ``m.__dict__ = {}``).  Modifying
 :attr:`__dict__` directly is not recommended.
 
 Modules built into the interpreter are written like this: ``<module 'sys'
 (built-in)>``.  If loaded from a file, they are written as ``<module 'os' from
-'/usr/local/lib/python|version|/os.pyc'>``.
+'/usr/local/lib/pythonX.Y/os.pyc'>``.
 
 
 .. _typesobjects:
 
 Classes and Class Instances
 ---------------------------
 
-.. _classes and instances:
-
-See chapters 3 and 7 of the Python Reference Manual (XXX reference:
-../ref/ref.html) for these.
+See :ref:`objects` and :ref:`class` for these.
 
 
 .. _typesfunctions:
 
 Functions
 ---------
 
 Function objects are created by function definitions.  The only operation on a
 function object is to call it: ``func(argument-list)``.
 
-There are really two flavors of function objects: built-in functions and user-
-defined functions.  Both support the same operation (to call the function), but
-the implementation is different, hence the different object types.
+There are really two flavors of function objects: built-in functions and
+user-defined functions.  Both support the same operation (to call the function),
+but the implementation is different, hence the different object types.
 
-See the Python Reference Manual (XXX reference: ../ref/ref.html) for more
-information.
+See :ref:`function` for more information.
 
 
 .. _typesmethods:
 
 Methods
 -------
 
 .. index:: object: method
 
 Methods are functions that are called using the attribute notation. There are
 two flavors: built-in methods (such as :meth:`append` on lists) and class
 instance methods.  Built-in methods are described with the types that support
@@ -2168,55 +2498,53 @@
 object (``meth.im_func``), setting method attributes on either bound or unbound
 methods is disallowed.  Attempting to set a method attribute results in a
 :exc:`TypeError` being raised.  In order to set a method attribute, you need to
 explicitly set it on the underlying function object::
 
    class C:
        def method(self):
            pass
 
    c = C()
    c.method.im_func.whoami = 'my name is c'
 
-See the Python Reference Manual (XXX reference: ../ref/ref.html) for more
-information.
+See :ref:`types` for more information.
 
 
 .. _bltin-code-objects:
 
 Code Objects
 ------------
 
 .. index:: object: code
 
 .. index::
    builtin: compile
    single: func_code (function object attribute)
 
 Code objects are used by the implementation to represent "pseudo-compiled"
 executable Python code such as a function body. They differ from function
 objects because they don't contain a reference to their global execution
 environment.  Code objects are returned by the built-in :func:`compile` function
 and can be extracted from function objects through their :attr:`func_code`
-attribute.
+attribute. See also the :mod:`code` module.
 
 .. index::
    statement: exec
    builtin: eval
 
 A code object can be executed or evaluated by passing it (instead of a source
 string) to the :keyword:`exec` statement or the built-in :func:`eval` function.
 
-See the Python Reference Manual (XXX reference: ../ref/ref.html) for more
-information.
+See :ref:`types` for more information.
 
 
 .. _bltin-type-objects:
 
 Type Objects
 ------------
 
 .. index::
    builtin: type
    module: types
 
 Type objects represent the various object types.  An object's type is accessed
@@ -2235,27 +2563,27 @@
 This object is returned by functions that don't explicitly return a value.  It
 supports no special operations.  There is exactly one null object, named
 ``None`` (a built-in name).
 
 It is written as ``None``.
 
 
 .. _bltin-ellipsis-object:
 
 The Ellipsis Object
 -------------------
 
-This object is used by extended slice notation (see the Python Reference Manual
-(XXX reference: ../ref/ref.html)).  It supports no special operations.  There is
-exactly one ellipsis object, named :const:`Ellipsis` (a built-in name).
+This object is used by extended slice notation (see :ref:`slicings`).  It
+supports no special operations.  There is exactly one ellipsis object, named
+:const:`Ellipsis` (a built-in name).
 
 It is written as ``Ellipsis``.
 
 
 Boolean Values
 --------------
 
 Boolean values are the two constant objects ``False`` and ``True``.  They are
 used to represent truth values (although other values can also be considered
 false or true).  In numeric contexts (for example when used as the argument to
 an arithmetic operator), they behave like the integers 0 and 1, respectively.
 The built-in function :func:`bool` can be used to cast any value to a Boolean,
@@ -2266,27 +2594,26 @@
    single: False
    single: True
    pair: Boolean; values
 
 They are written as ``False`` and ``True``, respectively.
 
 
 .. _typesinternal:
 
 Internal Objects
 ----------------
 
-See the Python Reference Manual (XXX reference: ../ref/ref.html) for this
-information.  It describes stack frame objects, traceback objects, and slice
-objects.
+See :ref:`types` for this information.  It describes stack frame objects,
+traceback objects, and slice objects.
 
 
 .. _specialattrs:
 
 Special Attributes
 ==================
 
 The implementation adds a few special read-only attributes to several object
 types, where they are relevant.  Some of these are not reported by the
 :func:`dir` built-in function.
 
 
@@ -2316,38 +2643,60 @@
 
 
 .. attribute:: class.__bases__
 
    The tuple of base classes of a class object.  If there are no base classes, this
    will be an empty tuple.
 
 
 .. attribute:: class.__name__
 
    The name of the class or type.
 
+
+The following attributes are only supported by :term:`new-style class`\ es.
+
+.. attribute:: class.__mro__
+
+   This attribute is a tuple of classes that are considered when looking for
+   base classes during method resolution.
+
+
+.. method:: class.mro()
+
+   This method can be overridden by a metaclass to customize the method
+   resolution order for its instances.  It is called at class instantiation, and
+   its result is stored in :attr:`__mro__`.
+
+
+.. method:: class.__subclasses__
+
+   Each new-style class keeps a list of weak references to its immediate
+   subclasses.  This method returns a list of all those references still alive.
+   Example::
+
+      >>> int.__subclasses__()
+      [<type 'bool'>]
+
+
 .. rubric:: Footnotes
 
-.. [#] Additional  information on these special methods may be found in the Python
-   Reference Manual (XXX reference: ../ref/ref.html).
+.. [#] Additional information on these special methods may be found in the Python
+   Reference Manual (:ref:`customization`).
 
 .. [#] As a consequence, the list ``[1, 2]`` is considered equal to ``[1.0, 2.0]``, and
    similarly for tuples.
 
 .. [#] They must have since the parser can't tell the type of the operands.
 
 .. [#] To format only a tuple you should therefore provide a singleton tuple whose only
    element is the tuple to be formatted.
 
 .. [#] These numbers are fairly arbitrary.  They are intended to avoid printing endless
    strings of meaningless digits without hampering correct use and without having
    to know the exact precision of floating point values on a particular machine.
 
-.. [#] :func:`file` is new in Python 2.2.  The older built-in :func:`open` is an alias
-   for :func:`file`.
-
 .. [#] The advantage of leaving the newline on is that returning an empty string is
    then an unambiguous EOF indication.  It is also possible (in cases where it
    might matter, for example, if you want to make an exact copy of a file while
    scanning its lines) to tell whether the last line of a file ended in a newline
    or not (yes this happens!).
-
