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.. XXX this whole file is outdated
:mod:`StringIO` --- Read and write strings as files
===================================================
.. module:: StringIO
:synopsis: Read and write strings as if they were files.
This module implements a file-like class, :class:`StringIO`, that reads and
writes a string buffer (also known as *memory files*). See the description of
file objects for operations (section :ref:`bltin-file-objects`). (For
standard strings, see :class:`str`.)
.. class:: StringIO([buffer])
When a :class:`StringIO` object is created, it can be initialized to an existing
string by passing the string to the constructor. If no string is given, the
:class:`StringIO` will start empty. In both cases, the initial file position
starts at zero.
The following methods of :class:`StringIO` objects require special mention:
.. method:: StringIO.getvalue()
Retrieve the entire contents of the "file" at any time before the
:class:`StringIO` object's :meth:`close` method is called.
.. method:: StringIO.close()
Free the memory buffer.
Example usage::
import StringIO
output = StringIO.StringIO()
output.write('First line.\n')
print('Second line.', file=output)
# Retrieve file contents -- this will be
# 'First line.\nSecond line.\n'
contents = output.getvalue()
# Close object and discard memory buffer --
# .getvalue() will now raise an exception.
output.close()
:mod:`cStringIO` --- Faster version of :mod:`StringIO`
======================================================
.. module:: cStringIO
:synopsis: Faster version of StringIO, but not subclassable.
.. moduleauthor:: Jim Fulton <jim@zope.com>
.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
The module :mod:`cStringIO` provides an interface similar to that of the
:mod:`StringIO` module. Heavy use of :class:`StringIO.StringIO` objects can be
made more efficient by using the function :func:`StringIO` from this module
instead.
Since this module provides a factory function which returns objects of built-in
types, there's no way to build your own version using subclassing. Use the
original :mod:`StringIO` module in that case.
Unlike the memory files implemented by the :mod:`StringIO` module, those
provided by this module are not able to accept strings that cannot be
encoded in plain ASCII.
Calling :func:`StringIO` with a string parameter populates
the object with the buffer representation of the string, instead of
encoding the string.
Another difference from the :mod:`StringIO` module is that calling
:func:`StringIO` with a string parameter creates a read-only object. Unlike an
object created without a string parameter, it does not have write methods.
These objects are not generally visible. They turn up in tracebacks as
:class:`StringI` and :class:`StringO`.
The following data objects are provided as well:
.. data:: InputType
The type object of the objects created by calling :func:`StringIO` with a string
parameter.
.. data:: OutputType
The type object of the objects returned by calling :func:`StringIO` with no
parameters.
There is a C API to the module as well; refer to the module source for more
information.
Example usage::
import cStringIO
output = cStringIO.StringIO()
output.write('First line.\n')
print('Second line.', file=output)
# Retrieve file contents -- this will be
# 'First line.\nSecond line.\n'
contents = output.getvalue()
# Close object and discard memory buffer --
# .getvalue() will now raise an exception.
output.close()
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