summaryrefslogtreecommitdiffstats
path: root/Doc/library/stringio.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Doc/library/stringio.rst')
-rw-r--r--Doc/library/stringio.rst122
1 files changed, 122 insertions, 0 deletions
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()
+