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diff --git a/Doc/library/stringio.rst b/Doc/library/stringio.rst new file mode 100644 index 0000000..9e2f0da --- /dev/null +++ b/Doc/library/stringio.rst @@ -0,0 +1,122 @@ + +: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`). + + +.. 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 :class:`StringIO` object can accept either Unicode or 8-bit strings, but + mixing the two may take some care. If both are used, 8-bit strings that cannot + be interpreted as 7-bit ASCII (that use the 8th bit) will cause a + :exc:`UnicodeError` to be raised when :meth:`getvalue` is called. + +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. See the note above + for information about mixing Unicode and 8-bit strings; such mixing can cause + this method to raise :exc:`UnicodeError`. + + +.. method:: StringIO.close() + + Free the memory buffer. + +Example usage:: + + import StringIO + + output = StringIO.StringIO() + output.write('First line.\n') + print >>output, 'Second line.' + + # 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 Unicode strings that cannot be +encoded as plain ASCII strings. + +Calling :func:`StringIO` with a Unicode string parameter populates +the object with the buffer representation of the Unicode 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 >>output, 'Second line.' + + # 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() + |