10:237 + ˆl–Ým_JJh¥² ¸È®2ú˜´o¿ ƒuð=_‡I|¥ŠèªÃÂä :mod:`bz2` --- Compression compatible with :program:`bzip2` =========================================================== .. module:: bz2 :synopsis: Interface to compression and decompression routines compatible with bzip2. .. moduleauthor:: Gustavo Niemeyer .. sectionauthor:: Gustavo Niemeyer .. versionadded:: 2.3 This module provides a comprehensive interface for the bz2 compression library. It implements a complete file interface, one-shot (de)compression functions, and types for sequential (de)compression. Here is a summary of the features offered by the bz2 module: * :class:`BZ2File` class implements a complete file interface, including :meth:`~BZ2File.readline`, :meth:`~BZ2File.readlines`, :meth:`~BZ2File.writelines`, :meth:`~BZ2File.seek`, etc; * :class:`BZ2File` class implements emulated :meth:`~BZ2File.seek` support; * :class:`BZ2File` class implements universal newline support; * :class:`BZ2File` class offers an optimized line iteration using the readahead algorithm borrowed from file objects; * Sequential (de)compression supported by :class:`BZ2Compressor` and :class:`BZ2Decompressor` classes; * One-shot (de)compression supported by :func:`compress` and :func:`decompress` functions; * Thread safety uses individual locking mechanism. (De)compression of files ------------------------ Handling of compressed files is offered by the :class:`BZ2File` class. .. index:: single: universal newlines; bz2.BZ2File class .. class:: BZ2File(filename[, mode[, buffering[, compresslevel]]]) Open a bz2 file. Mode can be either ``'r'`` or ``'w'``, for reading (default) or writing. When opened for writing, the file will be created if it doesn't exist, and truncated otherwise. If *buffering* is given, ``0`` means unbuffered, and larger numbers specify the buffer size; the default is ``0``. If *compresslevel* is given, it must be a number between ``1`` and ``9``; the default is ``9``. Add a ``'U'`` to mode to open the file for input in :term:`universal newlines` mode. Any line ending in the input file will be seen as a ``'\n'`` in Python. Also, a file so opened gains the attribute :attr:`newlines`; the value for this attribute is one of ``None`` (no newline read yet), ``'\r'``, ``'\n'``, ``'\r\n'`` or a tuple containing all the newline types seen. Universal newlines are available only when reading. Instances support iteration in the same way as normal :class:`file` instances. :class:`BZ2File` supports the :keyword:`with` statement. .. versionchanged:: 2.7 Support for the :keyword:`with` statement was added. .. note:: This class does not support input files containing multiple streams (such as those produced by the :program:`pbzip2` tool). When reading such an input file, only the first stream will be accessible. If you require support for multi-stream files, consider using the third-party :mod:`bz2file` module (available from `PyPI `_). This module provides a backport of Python 3.3's :class:`BZ2File` class, which does support multi-stream files. .. method:: close() Close the file. Sets data attribute :attr:`closed` to true. A closed file cannot be used for further I/O operations. :meth:`close` may be called more than once without error. .. method:: read([size]) Read at most *size* uncompressed bytes, returned as a string. If the *size* argument is negative or omitted, read until EOF is reached. .. method:: readline([size]) Return the next line from the file, as a string, retaining newline. A non-negative *size* argument limits the maximum number of bytes to return (an incomplete line may be returned then). Return an empty string at EOF. .. method:: readlines([size]) Return a list of lines read. The optional *size* argument, if given, is an approximate bound o