--- rest25/tutorial/inputoutput.rst	2008-12-19 16:58:06.000000000 +0900
+++ rest262/tutorial/inputoutput.rst	2009-04-05 05:01:50.000000000 +0900
@@ -18,34 +18,29 @@
 the :keyword:`print` statement.  (A third way is using the :meth:`write` method
 of file objects; the standard output file can be referenced as ``sys.stdout``.
 See the Library Reference for more information on this.)
 
 .. index:: module: string
 
 Often you'll want more control over the formatting of your output than simply
 printing space-separated values.  There are two ways to format your output; the
 first way is to do all the string handling yourself; using string slicing and
 concatenation operations you can create any layout you can imagine.  The
 standard module :mod:`string` contains some useful operations for padding
 strings to a given column width; these will be discussed shortly.  The second
-way is to use the ``%`` operator with a string as the left argument.  The ``%``
-operator interprets the left argument much like a :cfunc:`sprintf`\ -style
-format string to be applied to the right argument, and returns the string
-resulting from this formatting operation.
+way is to use the :meth:`str.format` method.
 
 One question remains, of course: how do you convert values to strings? Luckily,
 Python has ways to convert any value to a string: pass it to the :func:`repr`
-or :func:`str` functions.  Reverse quotes (``````) are equivalent to
-:func:`repr`, but they are no longer used in modern Python code and will likely
-not be in future versions of the language.
+or :func:`str` functions.
 
 The :func:`str` function is meant to return representations of values which are
 fairly human-readable, while :func:`repr` is meant to generate representations
 which can be read by the interpreter (or will force a :exc:`SyntaxError` if
 there is not equivalent syntax).  For objects which don't have a particular
 representation for human consumption, :func:`str` will return the same value as
 :func:`repr`.  Many values, such as numbers or structures like lists and
 dictionaries, have the same representation using either function.  Strings and
 floating point numbers, in particular, have two distinct representations.
 
 Some examples::
 
@@ -62,155 +57,204 @@
    >>> y = 200 * 200
    >>> s = 'The value of x is ' + repr(x) + ', and y is ' + repr(y) + '...'
    >>> print s
    The value of x is 32.5, and y is 40000...
    >>> # The repr() of a string adds string quotes and backslashes:
    ... hello = 'hello, world\n'
    >>> hellos = repr(hello)
    >>> print hellos
    'hello, world\n'
    >>> # The argument to repr() may be any Python object:
    ... repr((x, y, ('spam', 'eggs')))
    "(32.5, 40000, ('spam', 'eggs'))"
-   >>> # reverse quotes are convenient in interactive sessions:
-   ... `x, y, ('spam', 'eggs')`
-   "(32.5, 40000, ('spam', 'eggs'))"
 
 Here are two ways to write a table of squares and cubes::
 
    >>> for x in range(1, 11):
    ...     print repr(x).rjust(2), repr(x*x).rjust(3),
    ...     # Note trailing comma on previous line
    ...     print repr(x*x*x).rjust(4)
    ...
     1   1    1
     2   4    8
     3   9   27
     4  16   64
     5  25  125
     6  36  216
     7  49  343
     8  64  512
     9  81  729
    10 100 1000
+
    >>> for x in range(1,11):
-   ...     print '%2d %3d %4d' % (x, x*x, x*x*x)
-   ... 
+   ...     print '{0:2d} {1:3d} {2:4d}'.format(x, x*x, x*x*x)
+   ...
     1   1    1
     2   4    8
     3   9   27
     4  16   64
     5  25  125
     6  36  216
     7  49  343
     8  64  512
     9  81  729
    10 100 1000
 
-(Note that one space between each column was added by the way :keyword:`print`
-works: it always adds spaces between its arguments.)
+(Note that in the first example, one space between each column was added by the
+way :keyword:`print` works: it always adds spaces between its arguments.)
 
 This example demonstrates the :meth:`rjust` method of string objects, which
 right-justifies a string in a field of a given width by padding it with spaces
 on the left.  There are similar methods :meth:`ljust` and :meth:`center`.  These
 methods do not write anything, they just return a new string.  If the input
 string is too long, they don't truncate it, but return it unchanged; this will
 mess up your column lay-out but that's usually better than the alternative,
 which would be lying about a value.  (If you really want truncation you can
 always add a slice operation, as in ``x.ljust(n)[:n]``.)
 
 There is another method, :meth:`zfill`, which pads a numeric string on the left
 with zeros.  It understands about plus and minus signs::
 
    >>> '12'.zfill(5)
    '00012'
    >>> '-3.14'.zfill(7)
    '-003.14'
    >>> '3.14159265359'.zfill(5)
    '3.14159265359'
 
-Using the ``%`` operator looks like this::
+Basic usage of the :meth:`str.format` method looks like this::
+
+   >>> print 'We are the {0} who say "{1}!"'.format('knights', 'Ni')
+   We are the knights who say "Ni!"
+
+The brackets and characters within them (called format fields) are replaced with
+the objects passed into the format method.  The number in the brackets refers to
+the position of the object passed into the format method. ::
+
+   >>> print '{0} and {1}'.format('spam', 'eggs')
+   spam and eggs
+   >>> print '{1} and {0}'.format('spam', 'eggs')
+   eggs and spam
+
+If keyword arguments are used in the format method, their values are referred to
+by using the name of the argument. ::
+
+   >>> print 'This {food} is {adjective}.'.format(
+   ...       food='spam', adjective='absolutely horrible')
+   This spam is absolutely horrible.
+
+Positional and keyword arguments can be arbitrarily combined::
+
+   >>> print 'The story of {0}, {1}, and {other}.'.format('Bill', 'Manfred',
+   ...                                                    other='Georg')
+   The story of Bill, Manfred, and Georg.
+
+An optional ``':'`` and format specifier can follow the field name. This also
+greater control over how the value is formatted.  The following example
+truncates the Pi to three places after the decimal.
 
    >>> import math
-   >>> print 'The value of PI is approximately %5.3f.' % math.pi
+   >>> print 'The value of PI is approximately {0:.3f}.'.format(math.pi)
    The value of PI is approximately 3.142.
 
-If there is more than one format in the string, you need to pass a tuple as
-right operand, as in this example::
+Passing an integer after the ``':'`` will cause that field to be a minimum
+number of characters wide.  This is useful for making tables pretty.::
 
    >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678}
    >>> for name, phone in table.items():
-   ...     print '%-10s ==> %10d' % (name, phone)
-   ... 
+   ...     print '{0:10} ==> {1:10d}'.format(name, phone)
+   ...
    Jack       ==>       4098
    Dcab       ==>       7678
    Sjoerd     ==>       4127
 
-Most formats work exactly as in C and require that you pass the proper type;
-however, if you don't you get an exception, not a core dump. The ``%s`` format
-is more relaxed: if the corresponding argument is not a string object, it is
-converted to string using the :func:`str` built-in function.  Using ``*`` to
-pass the width or precision in as a separate (integer) argument is supported.
-The C formats ``%n`` and ``%p`` are not supported.
-
 If you have a really long format string that you don't want to split up, it
 would be nice if you could reference the variables to be formatted by name
-instead of by position.  This can be done by using form ``%(name)format``, as
-shown here::
+instead of by position.  This can be done by simply passing the dict and using
+square brackets ``'[]'`` to access the keys ::
 
    >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
-   >>> print 'Jack: %(Jack)d; Sjoerd: %(Sjoerd)d; Dcab: %(Dcab)d' % table
+   >>> print ('Jack: {0[Jack]:d}; Sjoerd: {0[Sjoerd]:d}; '
+   ...        'Dcab: {0[Dcab]:d}'.format(table))
+   Jack: 4098; Sjoerd: 4127; Dcab: 8637678
+
+This could also be done by passing the table as keyword arguments with the '**'
+notation.::
+
+   >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
+   >>> print 'Jack: {Jack:d}; Sjoerd: {Sjoerd:d}; Dcab: {Dcab:d}'.format(**table)
    Jack: 4098; Sjoerd: 4127; Dcab: 8637678
 
 This is particularly useful in combination with the new built-in :func:`vars`
 function, which returns a dictionary containing all local variables.
 
+For a complete overview of string formating with :meth:`str.format`, see
+:ref:`formatstrings`.
+
+
+Old string formatting
+---------------------
+
+The ``%`` operator can also be used for string formatting. It interprets the
+left argument much like a :cfunc:`sprintf`\ -style format string to be applied
+to the right argument, and returns the string resulting from this formatting
+operation. For example::
+
+   >>> import math
+   >>> print 'The value of PI is approximately %5.3f.' % math.pi
+   The value of PI is approximately 3.142.
+
+Since :meth:`str.format` is quite new, a lot of Python code still uses the ``%``
+operator. However, because this old style of formatting will eventually removed
+from the language :meth:`str.format` should generally be used.
+
+More information can be found in the :ref:`string-formatting` section.
+
 
 .. _tut-files:
 
 Reading and Writing Files
 =========================
 
 .. index::
    builtin: open
    object: file
 
 :func:`open` returns a file object, and is most commonly used with two
 arguments: ``open(filename, mode)``.
 
-.. % Opening files
-
 ::
 
-   >>> f=open('/tmp/workfile', 'w')
+   >>> f = open('/tmp/workfile', 'w')
    >>> print f
    <open file '/tmp/workfile', mode 'w' at 80a0960>
 
 The first argument is a string containing the filename.  The second argument is
 another string containing a few characters describing the way in which the file
 will be used.  *mode* can be ``'r'`` when the file will only be read, ``'w'``
 for only writing (an existing file with the same name will be erased), and
 ``'a'`` opens the file for appending; any data written to the file is
 automatically added to the end.  ``'r+'`` opens the file for both reading and
 writing. The *mode* argument is optional; ``'r'`` will be assumed if it's
 omitted.
 
-On Windows and the Macintosh, ``'b'`` appended to the mode opens the file in
-binary mode, so there are also modes like ``'rb'``, ``'wb'``, and ``'r+b'``.
-Windows makes a distinction between text and binary files; the end-of-line
-characters in text files are automatically altered slightly when data is read or
-written.  This behind-the-scenes modification to file data is fine for ASCII
-text files, but it'll corrupt binary data like that in :file:`JPEG` or
-:file:`EXE` files.  Be very careful to use binary mode when reading and writing
-such files.
+On Windows, ``'b'`` appended to the mode opens the file in binary mode, so there
+are also modes like ``'rb'``, ``'wb'``, and ``'r+b'``.  Windows makes a
+distinction between text and binary files; the end-of-line characters in text
+files are automatically altered slightly when data is read or written.  This
+behind-the-scenes modification to file data is fine for ASCII text files, but
+it'll corrupt binary data like that in :file:`JPEG` or :file:`EXE` files.  Be
+very careful to use binary mode when reading and writing such files.  On Unix,
+it doesn't hurt to append a ``'b'`` to the mode, so you can use it
+platform-independently for all binary files.
 
 
 .. _tut-filemethods:
 
 Methods of File Objects
 -----------------------
 
 The rest of the examples in this section will assume that a file object called
 ``f`` has already been created.
 
 To read a file's contents, call ``f.read(size)``, which reads some quantity of
 data and returns it as a string.  *size* is an optional numeric argument.  When
@@ -240,25 +284,25 @@
    ''
 
 ``f.readlines()`` returns a list containing all the lines of data in the file.
 If given an optional parameter *sizehint*, it reads that many bytes from the
 file and enough more to complete a line, and returns the lines from that.  This
 is often used to allow efficient reading of a large file by lines, but without
 having to load the entire file in memory.  Only complete lines will be returned.
 ::
 
    >>> f.readlines()
    ['This is the first line of the file.\n', 'Second line of the file\n']
 
-An alternate approach to reading lines is to loop over the file object. This is
+An alternative approach to reading lines is to loop over the file object. This is
 memory efficient, fast, and leads to simpler code::
 
    >>> for line in f:
            print line,
 
    This is the first line of the file.
    Second line of the file
 
 The alternative approach is simpler but does not provide as fine-grained
 control.  Since the two approaches manage line buffering differently, they
 should not be mixed.
 
@@ -277,81 +321,87 @@
 ``f.tell()`` returns an integer giving the file object's current position in the
 file, measured in bytes from the beginning of the file.  To change the file
 object's position, use ``f.seek(offset, from_what)``.  The position is computed
 from adding *offset* to a reference point; the reference point is selected by
 the *from_what* argument.  A *from_what* value of 0 measures from the beginning
 of the file, 1 uses the current file position, and 2 uses the end of the file as
 the reference point.  *from_what* can be omitted and defaults to 0, using the
 beginning of the file as the reference point. ::
 
    >>> f = open('/tmp/workfile', 'r+')
    >>> f.write('0123456789abcdef')
    >>> f.seek(5)     # Go to the 6th byte in the file
-   >>> f.read(1)        
+   >>> f.read(1)
    '5'
    >>> f.seek(-3, 2) # Go to the 3rd byte before the end
    >>> f.read(1)
    'd'
 
 When you're done with a file, call ``f.close()`` to close it and free up any
 system resources taken up by the open file.  After calling ``f.close()``,
 attempts to use the file object will automatically fail. ::
 
    >>> f.close()
    >>> f.read()
    Traceback (most recent call last):
      File "<stdin>", line 1, in ?
    ValueError: I/O operation on closed file
 
+It is good practice to use the :keyword:`with` keyword when dealing with file
+objects.  This has the advantage that the file is properly closed after its
+suite finishes, even if an exception is raised on the way.  It is also much
+shorter than writing equivalent :keyword:`try`\ -\ :keyword:`finally` blocks::
+
+    >>> with open('/tmp/workfile', 'r') as f:
+    ...     read_data = f.read()
+    >>> f.closed
+    True
+
 File objects have some additional methods, such as :meth:`isatty` and
 :meth:`truncate` which are less frequently used; consult the Library Reference
 for a complete guide to file objects.
 
 
 .. _tut-pickle:
 
 The :mod:`pickle` Module
 ------------------------
 
 .. index:: module: pickle
 
 Strings can easily be written to and read from a file. Numbers take a bit more
 effort, since the :meth:`read` method only returns strings, which will have to
 be passed to a function like :func:`int`, which takes a string like ``'123'``
 and returns its numeric value 123.  However, when you want to save more complex
 data types like lists, dictionaries, or class instances, things get a lot more
 complicated.
 
 Rather than have users be constantly writing and debugging code to save
-complicated data types, Python provides a standard module called :mod:`pickle`
-(XXX reference: ../lib/module-pickle.html).  This is an amazing module that can
-take almost any Python object (even some forms of Python code!), and convert it
-to a string representation; this process is called :dfn:`pickling`.
-Reconstructing the object from the string representation is called
-:dfn:`unpickling`.  Between pickling and unpickling, the string representing the
-object may have been stored in a file or data, or sent over a network connection
-to some distant machine.
+complicated data types, Python provides a standard module called :mod:`pickle`.
+This is an amazing module that can take almost any Python object (even some
+forms of Python code!), and convert it to a string representation; this process
+is called :dfn:`pickling`.  Reconstructing the object from the string
+representation is called :dfn:`unpickling`.  Between pickling and unpickling,
+the string representing the object may have been stored in a file or data, or
+sent over a network connection to some distant machine.
 
 If you have an object ``x``, and a file object ``f`` that's been opened for
 writing, the simplest way to pickle the object takes only one line of code::
 
    pickle.dump(x, f)
 
 To unpickle the object again, if ``f`` is a file object which has been opened
 for reading::
 
    x = pickle.load(f)
 
 (There are other variants of this, used when pickling many objects or when you
 don't want to write the pickled data to a file; consult the complete
-documentation for :mod:`pickle` (XXX reference: ../lib/module-pickle.html) in
-the Python Library Reference (XXX reference: ../lib/).)
+documentation for :mod:`pickle` in the Python Library Reference.)
 
-:mod:`pickle` (XXX reference: ../lib/module-pickle.html) is the standard way to
-make Python objects which can be stored and reused by other programs or by a
+:mod:`pickle` is the standard way to make Python objects which can be stored and
-future invocation of the same program; the technical term for this is a
+reused by other programs or by a future invocation of the same program; the
+technical term for this is a :dfn:`persistent` object.  Because :mod:`pickle` is
-:dfn:`persistent` object.  Because :mod:`pickle` (XXX reference: ../lib/module-
+so widely used, many authors who write Python extensions take care to ensure
-pickle.html) is so widely used, many authors who write Python extensions take
-care to ensure that new data types such as matrices can be properly pickled and
-unpickled.
+that new data types such as matrices can be properly pickled and unpickled.
 
 
