<!DOCTYPE html>
<html lang="en" data-content_root="../">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<meta property="og:title" content="bz2 — Support for bzip2 compression" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://docs.python.org/3/library/bz2.html" />
<meta property="og:site_name" content="Python documentation" />
<meta property="og:description" content="Source code: Lib/bz2.py This module provides a comprehensive interface for compressing and decompressing data using the bzip2 compression algorithm. The bz2 module contains: The open() function and..." />
<meta property="og:image" content="https://docs.python.org/3/_static/og-image.png" />
<meta property="og:image:alt" content="Python documentation" />
<meta name="description" content="Source code: Lib/bz2.py This module provides a comprehensive interface for compressing and decompressing data using the bzip2 compression algorithm. The bz2 module contains: The open() function and..." />
<meta property="og:image:width" content="200">
<meta property="og:image:height" content="200">
<meta name="theme-color" content="#3776ab">
<title>bz2 — Support for bzip2 compression — Python 3.13.3 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=b86133f3" />
<link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=23252803" />
<link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=5349f25f" />
<script src="../_static/documentation_options.js?v=5d57ca2d"></script>
<script src="../_static/doctools.js?v=9bcbadda"></script>
<script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
<script src="../_static/sidebar.js"></script>
<link rel="search" type="application/opensearchdescription+xml"
title="Search within Python 3.13.3 documentation"
href="../_static/opensearch.xml"/>
<link rel="author" title="About these documents" href="../about.html" />
<link rel="index" title="Index" href="../genindex.html" />
<link rel="search" title="Search" href="../search.html" />
<link rel="copyright" title="Copyright" href="../copyright.html" />
<link rel="next" title="lzma — Compression using the LZMA algorithm" href="lzma.html" />
<link rel="prev" title="gzip — Support for gzip files" href="gzip.html" />
<link rel="canonical" href="https://docs.python.org/3/library/bz2.html">
<style>
@media only screen {
table.full-width-table {
width: 100%;
}
}
</style>
<link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
<link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
<script type="text/javascript" src="../_static/copybutton.js"></script>
<script type="text/javascript" src="../_static/menu.js"></script>
<script type="text/javascript" src="../_static/search-focus.js"></script>
<script type="text/javascript" src="../_static/themetoggle.js"></script>
<script type="text/javascript" src="../_static/rtd_switcher.js"></script>
<meta name="readthedocs-addons-api-version" content="1">
</head>
<body>
<div class="mobile-nav">
<input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
<nav class="nav-content" role="navigation">
<label for="menuToggler" class="toggler__label">
<span></span>
</label>
<span class="nav-items-wrapper">
<a href="https://www.python.org/" class="nav-logo">
<img src="../_static/py.svg" alt="Python logo"/>
</a>
<span class="version_switcher_placeholder"></span>
<form role="search" class="search" action="../search.html" method="get">
<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
<path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path>
</svg>
<input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
<input type="submit" value="Go"/>
</form>
</span>
</nav>
<div class="menu-wrapper">
<nav class="menu" role="navigation" aria-label="main navigation">
<div class="language_switcher_placeholder"></div>
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label>
<div>
<h3><a href="../contents.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code> — Support for <strong class="program">bzip2</strong> compression</a><ul>
<li><a class="reference internal" href="#de-compression-of-files">(De)compression of files</a></li>
<li><a class="reference internal" href="#incremental-de-compression">Incremental (de)compression</a></li>
<li><a class="reference internal" href="#one-shot-de-compression">One-shot (de)compression</a></li>
<li><a class="reference internal" href="#examples-of-usage">Examples of usage</a></li>
</ul>
</li>
</ul>
</div>
<div>
<h4>Previous topic</h4>
<p class="topless"><a href="gzip.html"
title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">gzip</span></code> — Support for <strong class="program">gzip</strong> files</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="lzma.html"
title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code> — Compression using the LZMA algorithm</a></p>
</div>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">Report a Bug</a></li>
<li>
<a href="https://github.com/python/cpython/blob/main/Doc/library/bz2.rst"
rel="nofollow">Show Source
</a>
</li>
</ul>
</div>
</nav>
</div>
</div>
<div class="related" role="navigation" aria-label="Related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="lzma.html" title="lzma — Compression using the LZMA algorithm"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="gzip.html" title="gzip — Support for gzip files"
accesskey="P">previous</a> |</li>
<li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> »</li>
<li class="switchers">
<div class="language_switcher_placeholder"></div>
<div class="version_switcher_placeholder"></div>
</li>
<li>
</li>
<li id="cpython-language-and-version">
<a href="../index.html">3.13.3 Documentation</a> »
</li>
<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li>
<li class="nav-item nav-item-2"><a href="archiving.html" accesskey="U">Data Compression and Archiving</a> »</li>
<li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code> — Support for <strong class="program">bzip2</strong> compression</a></li>
<li class="right">
<div class="inline-search" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
<input type="submit" value="Go" />
</form>
</div>
|
</li>
<li class="right">
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label> |</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section id="module-bz2">
<span id="bz2-support-for-bzip2-compression"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code> — Support for <strong class="program">bzip2</strong> compression<a class="headerlink" href="#module-bz2" title="Link to this heading">¶</a></h1>
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/bz2.py">Lib/bz2.py</a></p>
<hr class="docutils" />
<p>This module provides a comprehensive interface for compressing and
decompressing data using the bzip2 compression algorithm.</p>
<p>The <a class="reference internal" href="#module-bz2" title="bz2: Interfaces for bzip2 compression and decompression."><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code></a> module contains:</p>
<ul class="simple">
<li><p>The <a class="reference internal" href="#bz2.open" title="bz2.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> function and <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> class for reading and
writing compressed files.</p></li>
<li><p>The <a class="reference internal" href="#bz2.BZ2Compressor" title="bz2.BZ2Compressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Compressor</span></code></a> and <a class="reference internal" href="#bz2.BZ2Decompressor" title="bz2.BZ2Decompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Decompressor</span></code></a> classes for
incremental (de)compression.</p></li>
<li><p>The <a class="reference internal" href="#bz2.compress" title="bz2.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">compress()</span></code></a> and <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> functions for one-shot
(de)compression.</p></li>
</ul>
<section id="de-compression-of-files">
<h2>(De)compression of files<a class="headerlink" href="#de-compression-of-files" title="Link to this heading">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="bz2.open">
<span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">open</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'rb'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">compresslevel</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">9</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">encoding</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">errors</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">newline</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.open" title="Link to this definition">¶</a></dt>
<dd><p>Open a bzip2-compressed file in binary or text mode, returning a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file
object</span></a>.</p>
<p>As with the constructor for <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a>, the <em>filename</em> argument can be
an actual filename (a <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a> or <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object), or an existing
file object to read from or write to.</p>
<p>The <em>mode</em> argument can be any of <code class="docutils literal notranslate"><span class="pre">'r'</span></code>, <code class="docutils literal notranslate"><span class="pre">'rb'</span></code>, <code class="docutils literal notranslate"><span class="pre">'w'</span></code>, <code class="docutils literal notranslate"><span class="pre">'wb'</span></code>,
<code class="docutils literal notranslate"><span class="pre">'x'</span></code>, <code class="docutils literal notranslate"><span class="pre">'xb'</span></code>, <code class="docutils literal notranslate"><span class="pre">'a'</span></code> or <code class="docutils literal notranslate"><span class="pre">'ab'</span></code> for binary mode, or <code class="docutils literal notranslate"><span class="pre">'rt'</span></code>,
<code class="docutils literal notranslate"><span class="pre">'wt'</span></code>, <code class="docutils literal notranslate"><span class="pre">'xt'</span></code>, or <code class="docutils literal notranslate"><span class="pre">'at'</span></code> for text mode. The default is <code class="docutils literal notranslate"><span class="pre">'rb'</span></code>.</p>
<p>The <em>compresslevel</em> argument is an integer from 1 to 9, as for the
<a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> constructor.</p>
<p>For binary mode, this function is equivalent to the <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a>
constructor: <code class="docutils literal notranslate"><span class="pre">BZ2File(filename,</span> <span class="pre">mode,</span> <span class="pre">compresslevel=compresslevel)</span></code>. In
this case, the <em>encoding</em>, <em>errors</em> and <em>newline</em> arguments must not be
provided.</p>
<p>For text mode, a <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> object is created, and wrapped in an
<a class="reference internal" href="io.html#io.TextIOWrapper" title="io.TextIOWrapper"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.TextIOWrapper</span></code></a> instance with the specified encoding, error
handling behavior, and line ending(s).</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.4: </span>The <code class="docutils literal notranslate"><span class="pre">'x'</span></code> (exclusive creation) mode was added.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
</div>
</dd></dl>
<dl class="py class">
<dt class="sig sig-object py" id="bz2.BZ2File">
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">BZ2File</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">compresslevel</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">9</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File" title="Link to this definition">¶</a></dt>
<dd><p>Open a bzip2-compressed file in binary mode.</p>
<p>If <em>filename</em> is a <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a> or <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object, open the named file
directly. Otherwise, <em>filename</em> should be a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>, which will
be used to read or write the compressed data.</p>
<p>The <em>mode</em> argument can be either <code class="docutils literal notranslate"><span class="pre">'r'</span></code> for reading (default), <code class="docutils literal notranslate"><span class="pre">'w'</span></code> for
overwriting, <code class="docutils literal notranslate"><span class="pre">'x'</span></code> for exclusive creation, or <code class="docutils literal notranslate"><span class="pre">'a'</span></code> for appending. These
can equivalently be given as <code class="docutils literal notranslate"><span class="pre">'rb'</span></code>, <code class="docutils literal notranslate"><span class="pre">'wb'</span></code>, <code class="docutils literal notranslate"><span class="pre">'xb'</span></code> and <code class="docutils literal notranslate"><span class="pre">'ab'</span></code>
respectively.</p>
<p>If <em>filename</em> is a file object (rather than an actual file name), a mode of
<code class="docutils literal notranslate"><span class="pre">'w'</span></code> does not truncate the file, and is instead equivalent to <code class="docutils literal notranslate"><span class="pre">'a'</span></code>.</p>
<p>If <em>mode</em> is <code class="docutils literal notranslate"><span class="pre">'w'</span></code> or <code class="docutils literal notranslate"><span class="pre">'a'</span></code>, <em>compresslevel</em> can be an integer between
<code class="docutils literal notranslate"><span class="pre">1</span></code> and <code class="docutils literal notranslate"><span class="pre">9</span></code> specifying the level of compression: <code class="docutils literal notranslate"><span class="pre">1</span></code> produces the
least compression, and <code class="docutils literal notranslate"><span class="pre">9</span></code> (default) produces the most compression.</p>
<p>If <em>mode</em> is <code class="docutils literal notranslate"><span class="pre">'r'</span></code>, the input file may be the concatenation of multiple
compressed streams.</p>
<p><a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> provides all of the members specified by the
<a class="reference internal" href="io.html#io.BufferedIOBase" title="io.BufferedIOBase"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.BufferedIOBase</span></code></a>, except for <a class="reference internal" href="io.html#io.BufferedIOBase.detach" title="io.BufferedIOBase.detach"><code class="xref py py-meth docutils literal notranslate"><span class="pre">detach()</span></code></a>
and <a class="reference internal" href="io.html#io.IOBase.truncate" title="io.IOBase.truncate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">truncate()</span></code></a>.
Iteration and the <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> statement are supported.</p>
<p><a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> also provides the following methods and attributes:</p>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.peek">
<span class="sig-name descname"><span class="pre">peek</span></span><span class="sig-paren">(</span><span class="optional">[</span><em class="sig-param"><span class="n"><span class="pre">n</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.peek" title="Link to this definition">¶</a></dt>
<dd><p>Return buffered data without advancing the file position. At least one
byte of data will be returned (unless at EOF). The exact number of bytes
returned is unspecified.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>While calling <a class="reference internal" href="#bz2.BZ2File.peek" title="bz2.BZ2File.peek"><code class="xref py py-meth docutils literal notranslate"><span class="pre">peek()</span></code></a> does not change the file position of
the <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a>, it may change the position of the underlying file
object (e.g. if the <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a> was constructed by passing a file
object for <em>filename</em>).</p>
</div>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.fileno">
<span class="sig-name descname"><span class="pre">fileno</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.fileno" title="Link to this definition">¶</a></dt>
<dd><p>Return the file descriptor for the underlying file.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.readable">
<span class="sig-name descname"><span class="pre">readable</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.readable" title="Link to this definition">¶</a></dt>
<dd><p>Return whether the file was opened for reading.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.seekable">
<span class="sig-name descname"><span class="pre">seekable</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.seekable" title="Link to this definition">¶</a></dt>
<dd><p>Return whether the file supports seeking.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.writable">
<span class="sig-name descname"><span class="pre">writable</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.writable" title="Link to this definition">¶</a></dt>
<dd><p>Return whether the file was opened for writing.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.read1">
<span class="sig-name descname"><span class="pre">read1</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">size</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.read1" title="Link to this definition">¶</a></dt>
<dd><p>Read up to <em>size</em> uncompressed bytes, while trying to avoid
making multiple reads from the underlying stream. Reads up to a
buffer’s worth of data if size is negative.</p>
<p>Returns <code class="docutils literal notranslate"><span class="pre">b''</span></code> if the file is at EOF.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2File.readinto">
<span class="sig-name descname"><span class="pre">readinto</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">b</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2File.readinto" title="Link to this definition">¶</a></dt>
<dd><p>Read bytes into <em>b</em>.</p>
<p>Returns the number of bytes read (0 for EOF).</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="bz2.BZ2File.mode">
<span class="sig-name descname"><span class="pre">mode</span></span><a class="headerlink" href="#bz2.BZ2File.mode" title="Link to this definition">¶</a></dt>
<dd><p><code class="docutils literal notranslate"><span class="pre">'rb'</span></code> for reading and <code class="docutils literal notranslate"><span class="pre">'wb'</span></code> for writing.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.13.</span></p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="bz2.BZ2File.name">
<span class="sig-name descname"><span class="pre">name</span></span><a class="headerlink" href="#bz2.BZ2File.name" title="Link to this definition">¶</a></dt>
<dd><p>The bzip2 file name. Equivalent to the <a class="reference internal" href="io.html#io.FileIO.name" title="io.FileIO.name"><code class="xref py py-attr docutils literal notranslate"><span class="pre">name</span></code></a>
attribute of the underlying <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.13.</span></p>
</div>
</dd></dl>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.1: </span>Support for the <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> statement was added.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>Support was added for <em>filename</em> being a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a> instead of an
actual filename.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">'a'</span></code> (append) mode was added, along with support for reading
multi-stream files.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.4: </span>The <code class="docutils literal notranslate"><span class="pre">'x'</span></code> (exclusive creation) mode was added.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.5: </span>The <a class="reference internal" href="io.html#io.BufferedIOBase.read" title="io.BufferedIOBase.read"><code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code></a> method now accepts an argument of
<code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Accepts a <a class="reference internal" href="../glossary.html#term-path-like-object"><span class="xref std std-term">path-like object</span></a>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.9: </span>The <em>buffering</em> parameter has been removed. It was ignored and deprecated
since Python 3.0. Pass an open file object to control how the file is
opened.</p>
<p>The <em>compresslevel</em> parameter became keyword-only.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.10: </span>This class is thread unsafe in the face of multiple simultaneous
readers or writers, just like its equivalent classes in <a class="reference internal" href="gzip.html#module-gzip" title="gzip: Interfaces for gzip compression and decompression using file objects."><code class="xref py py-mod docutils literal notranslate"><span class="pre">gzip</span></code></a> and
<a class="reference internal" href="lzma.html#module-lzma" title="lzma: A Python wrapper for the liblzma compression library."><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code></a> have always been.</p>
</div>
</dd></dl>
</section>
<section id="incremental-de-compression">
<h2>Incremental (de)compression<a class="headerlink" href="#incremental-de-compression" title="Link to this heading">¶</a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="bz2.BZ2Compressor">
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">BZ2Compressor</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">compresslevel</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">9</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2Compressor" title="Link to this definition">¶</a></dt>
<dd><p>Create a new compressor object. This object may be used to compress data
incrementally. For one-shot compression, use the <a class="reference internal" href="#bz2.compress" title="bz2.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">compress()</span></code></a> function
instead.</p>
<p><em>compresslevel</em>, if given, must be an integer between <code class="docutils literal notranslate"><span class="pre">1</span></code> and <code class="docutils literal notranslate"><span class="pre">9</span></code>. The
default is <code class="docutils literal notranslate"><span class="pre">9</span></code>.</p>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2Compressor.compress">
<span class="sig-name descname"><span class="pre">compress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2Compressor.compress" title="Link to this definition">¶</a></dt>
<dd><p>Provide data to the compressor object. Returns a chunk of compressed data
if possible, or an empty byte string otherwise.</p>
<p>When you have finished providing data to the compressor, call the
<a class="reference internal" href="#bz2.BZ2Compressor.flush" title="bz2.BZ2Compressor.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a> method to finish the compression process.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2Compressor.flush">
<span class="sig-name descname"><span class="pre">flush</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2Compressor.flush" title="Link to this definition">¶</a></dt>
<dd><p>Finish the compression process. Returns the compressed data left in
internal buffers.</p>
<p>The compressor object may not be used after this method has been called.</p>
</dd></dl>
</dd></dl>
<dl class="py class">
<dt class="sig sig-object py" id="bz2.BZ2Decompressor">
<em class="property"><span class="k"><span class="pre">class</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">BZ2Decompressor</span></span><a class="headerlink" href="#bz2.BZ2Decompressor" title="Link to this definition">¶</a></dt>
<dd><p>Create a new decompressor object. This object may be used to decompress data
incrementally. For one-shot compression, use the <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> function
instead.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>This class does not transparently handle inputs containing multiple
compressed streams, unlike <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> and <a class="reference internal" href="#bz2.BZ2File" title="bz2.BZ2File"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2File</span></code></a>. If
you need to decompress a multi-stream input with <a class="reference internal" href="#bz2.BZ2Decompressor" title="bz2.BZ2Decompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Decompressor</span></code></a>,
you must use a new decompressor for each stream.</p>
</div>
<dl class="py method">
<dt class="sig sig-object py" id="bz2.BZ2Decompressor.decompress">
<span class="sig-name descname"><span class="pre">decompress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">max_length</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">-1</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.BZ2Decompressor.decompress" title="Link to this definition">¶</a></dt>
<dd><p>Decompress <em>data</em> (a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>), returning
uncompressed data as bytes. Some of <em>data</em> may be buffered
internally, for use in later calls to <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a>. The
returned data should be concatenated with the output of any
previous calls to <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a>.</p>
<p>If <em>max_length</em> is nonnegative, returns at most <em>max_length</em>
bytes of decompressed data. If this limit is reached and further
output can be produced, the <a class="reference internal" href="#bz2.BZ2Decompressor.needs_input" title="bz2.BZ2Decompressor.needs_input"><code class="xref py py-attr docutils literal notranslate"><span class="pre">needs_input</span></code></a> attribute will
be set to <code class="docutils literal notranslate"><span class="pre">False</span></code>. In this case, the next call to
<a class="reference internal" href="#bz2.BZ2Decompressor.decompress" title="bz2.BZ2Decompressor.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a> may provide <em>data</em> as <code class="docutils literal notranslate"><span class="pre">b''</span></code> to obtain
more of the output.</p>
<p>If all of the input data was decompressed and returned (either
because this was less than <em>max_length</em> bytes, or because
<em>max_length</em> was negative), the <a class="reference internal" href="#bz2.BZ2Decompressor.needs_input" title="bz2.BZ2Decompressor.needs_input"><code class="xref py py-attr docutils literal notranslate"><span class="pre">needs_input</span></code></a> attribute
will be set to <code class="docutils literal notranslate"><span class="pre">True</span></code>.</p>
<p>Attempting to decompress data after the end of stream is reached
raises an <a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">EOFError</span></code></a>. Any data found after the end of the
stream is ignored and saved in the <a class="reference internal" href="#bz2.BZ2Decompressor.unused_data" title="bz2.BZ2Decompressor.unused_data"><code class="xref py py-attr docutils literal notranslate"><span class="pre">unused_data</span></code></a> attribute.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.5: </span>Added the <em>max_length</em> parameter.</p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="bz2.BZ2Decompressor.eof">
<span class="sig-name descname"><span class="pre">eof</span></span><a class="headerlink" href="#bz2.BZ2Decompressor.eof" title="Link to this definition">¶</a></dt>
<dd><p><code class="docutils literal notranslate"><span class="pre">True</span></code> if the end-of-stream marker has been reached.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="bz2.BZ2Decompressor.unused_data">
<span class="sig-name descname"><span class="pre">unused_data</span></span><a class="headerlink" href="#bz2.BZ2Decompressor.unused_data" title="Link to this definition">¶</a></dt>
<dd><p>Data found after the end of the compressed stream.</p>
<p>If this attribute is accessed before the end of the stream has been
reached, its value will be <code class="docutils literal notranslate"><span class="pre">b''</span></code>.</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="bz2.BZ2Decompressor.needs_input">
<span class="sig-name descname"><span class="pre">needs_input</span></span><a class="headerlink" href="#bz2.BZ2Decompressor.needs_input" title="Link to this definition">¶</a></dt>
<dd><p><code class="docutils literal notranslate"><span class="pre">False</span></code> if the <a class="reference internal" href="#bz2.BZ2Decompressor.decompress" title="bz2.BZ2Decompressor.decompress"><code class="xref py py-meth docutils literal notranslate"><span class="pre">decompress()</span></code></a> method can provide more
decompressed data before requiring new uncompressed input.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.5.</span></p>
</div>
</dd></dl>
</dd></dl>
</section>
<section id="one-shot-de-compression">
<h2>One-shot (de)compression<a class="headerlink" href="#one-shot-de-compression" title="Link to this heading">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="bz2.compress">
<span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">compress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">compresslevel</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">9</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.compress" title="Link to this definition">¶</a></dt>
<dd><p>Compress <em>data</em>, a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>.</p>
<p><em>compresslevel</em>, if given, must be an integer between <code class="docutils literal notranslate"><span class="pre">1</span></code> and <code class="docutils literal notranslate"><span class="pre">9</span></code>. The
default is <code class="docutils literal notranslate"><span class="pre">9</span></code>.</p>
<p>For incremental compression, use a <a class="reference internal" href="#bz2.BZ2Compressor" title="bz2.BZ2Compressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Compressor</span></code></a> instead.</p>
</dd></dl>
<dl class="py function">
<dt class="sig sig-object py" id="bz2.decompress">
<span class="sig-prename descclassname"><span class="pre">bz2.</span></span><span class="sig-name descname"><span class="pre">decompress</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#bz2.decompress" title="Link to this definition">¶</a></dt>
<dd><p>Decompress <em>data</em>, a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>.</p>
<p>If <em>data</em> is the concatenation of multiple compressed streams, decompress
all of the streams.</p>
<p>For incremental decompression, use a <a class="reference internal" href="#bz2.BZ2Decompressor" title="bz2.BZ2Decompressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Decompressor</span></code></a> instead.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>Support for multi-stream inputs was added.</p>
</div>
</dd></dl>
</section>
<section id="examples-of-usage">
<span id="bz2-usage-examples"></span><h2>Examples of usage<a class="headerlink" href="#examples-of-usage" title="Link to this heading">¶</a></h2>
<p>Below are some examples of typical usage of the <a class="reference internal" href="#module-bz2" title="bz2: Interfaces for bzip2 compression and decompression."><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code></a> module.</p>
<p>Using <a class="reference internal" href="#bz2.compress" title="bz2.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">compress()</span></code></a> and <a class="reference internal" href="#bz2.decompress" title="bz2.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> to demonstrate round-trip compression:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span><span class="w"> </span><span class="nn">bz2</span>
<span class="gp">>>> </span><span class="n">data</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">"""</span><span class="se">\</span>
<span class="gp">... </span><span class="s2">Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue</span>
<span class="gp">... </span><span class="s2">nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,</span>
<span class="gp">... </span><span class="s2">sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus</span>
<span class="gp">... </span><span class="s2">pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.</span>
<span class="gp">... </span><span class="s2">Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo</span>
<span class="gp">... </span><span class="s2">felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum</span>
<span class="gp">... </span><span class="s2">dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""</span>
<span class="gp">>>> </span><span class="n">c</span> <span class="o">=</span> <span class="n">bz2</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="gp">>>> </span><span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">)</span> <span class="o">/</span> <span class="nb">len</span><span class="p">(</span><span class="n">c</span><span class="p">)</span> <span class="c1"># Data compression ratio</span>
<span class="go">1.513595166163142</span>
<span class="gp">>>> </span><span class="n">d</span> <span class="o">=</span> <span class="n">bz2</span><span class="o">.</span><span class="n">decompress</span><span class="p">(</span><span class="n">c</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">data</span> <span class="o">==</span> <span class="n">d</span> <span class="c1"># Check equality to original object after round-trip</span>
<span class="go">True</span>
</pre></div>
</div>
<p>Using <a class="reference internal" href="#bz2.BZ2Compressor" title="bz2.BZ2Compressor"><code class="xref py py-class docutils literal notranslate"><span class="pre">BZ2Compressor</span></code></a> for incremental compression:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span><span class="w"> </span><span class="nn">bz2</span>
<span class="gp">>>> </span><span class="k">def</span><span class="w"> </span><span class="nf">gen_data</span><span class="p">(</span><span class="n">chunks</span><span class="o">=</span><span class="mi">10</span><span class="p">,</span> <span class="n">chunksize</span><span class="o">=</span><span class="mi">1000</span><span class="p">):</span>
<span class="gp">... </span><span class="w"> </span><span class="sd">"""Yield incremental blocks of chunksize bytes."""</span>
<span class="gp">... </span> <span class="k">for</span> <span class="n">_</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">chunks</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">yield</span> <span class="sa">b</span><span class="s2">"z"</span> <span class="o">*</span> <span class="n">chunksize</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="n">comp</span> <span class="o">=</span> <span class="n">bz2</span><span class="o">.</span><span class="n">BZ2Compressor</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">out</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">""</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">chunk</span> <span class="ow">in</span> <span class="n">gen_data</span><span class="p">():</span>
<span class="gp">... </span> <span class="c1"># Provide data to the compressor object</span>
<span class="gp">... </span> <span class="n">out</span> <span class="o">=</span> <span class="n">out</span> <span class="o">+</span> <span class="n">comp</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="n">chunk</span><span class="p">)</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="c1"># Finish the compression process. Call this once you have</span>
<span class="gp">>>> </span><span class="c1"># finished providing data to the compressor.</span>
<span class="gp">>>> </span><span class="n">out</span> <span class="o">=</span> <span class="n">out</span> <span class="o">+</span> <span class="n">comp</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
</pre></div>
</div>
<p>The example above uses a very “nonrandom” stream of data
(a stream of <code class="docutils literal notranslate"><span class="pre">b"z"</span></code> chunks). Random data tends to compress poorly,
while ordered, repetitive data usually yields a high compression ratio.</p>
<p>Writing and reading a bzip2-compressed file in binary mode:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span><span class="w"> </span><span class="nn">bz2</span>
<span class="gp">>>> </span><span class="n">data</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">"""</span><span class="se">\</span>
<span class="gp">... </span><span class="s2">Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue</span>
<span class="gp">... </span><span class="s2">nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,</span>
<span class="gp">... </span><span class="s2">sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus</span>
<span class="gp">... </span><span class="s2">pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.</span>
<span class="gp">... </span><span class="s2">Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo</span>
<span class="gp">... </span><span class="s2">felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum</span>
<span class="gp">... </span><span class="s2">dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""</span>
<span class="gp">>>> </span><span class="k">with</span> <span class="n">bz2</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"myfile.bz2"</span><span class="p">,</span> <span class="s2">"wb"</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
<span class="gp">... </span> <span class="c1"># Write compressed data to file</span>
<span class="gp">... </span> <span class="n">unused</span> <span class="o">=</span> <span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="k">with</span> <span class="n">bz2</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s2">"myfile.bz2"</span><span class="p">,</span> <span class="s2">"rb"</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
<span class="gp">... </span> <span class="c1"># Decompress data from file</span>
<span class="gp">... </span> <span class="n">content</span> <span class="o">=</span> <span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="n">content</span> <span class="o">==</span> <span class="n">data</span> <span class="c1"># Check equality to original object after round-trip</span>
<span class="go">True</span>
</pre></div>
</div>
</section>
</section>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="Main">
<div class="sphinxsidebarwrapper">
<div>
<h3><a href="../contents.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code> — Support for <strong class="program">bzip2</strong> compression</a><ul>
<li><a class="reference internal" href="#de-compression-of-files">(De)compression of files</a></li>
<li><a class="reference internal" href="#incremental-de-compression">Incremental (de)compression</a></li>
<li><a class="reference internal" href="#one-shot-de-compression">One-shot (de)compression</a></li>
<li><a class="reference internal" href="#examples-of-usage">Examples of usage</a></li>
</ul>
</li>
</ul>
</div>
<div>
<h4>Previous topic</h4>
<p class="topless"><a href="gzip.html"
title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">gzip</span></code> — Support for <strong class="program">gzip</strong> files</a></p>
</div>
<div>
<h4>Next topic</h4>
<p class="topless"><a href="lzma.html"
title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">lzma</span></code> — Compression using the LZMA algorithm</a></p>
</div>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">Report a Bug</a></li>
<li>
<a href="https://github.com/python/cpython/blob/main/Doc/library/bz2.rst"
rel="nofollow">Show Source
</a>
</li>
</ul>
</div>
</div>
<div id="sidebarbutton" title="Collapse sidebar">
<span>«</span>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="Related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="right" >
<a href="lzma.html" title="lzma — Compression using the LZMA algorithm"
>next</a> |</li>
<li class="right" >
<a href="gzip.html" title="gzip — Support for gzip files"
>previous</a> |</li>
<li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> »</li>
<li class="switchers">
<div class="language_switcher_placeholder"></div>
<div class="version_switcher_placeholder"></div>
</li>
<li>
</li>
<li id="cpython-language-and-version">
<a href="../index.html">3.13.3 Documentation</a> »
</li>
<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li>
<li class="nav-item nav-item-2"><a href="archiving.html" >Data Compression and Archiving</a> »</li>
<li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">bz2</span></code> — Support for <strong class="program">bzip2</strong> compression</a></li>
<li class="right">
<div class="inline-search" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
<input type="submit" value="Go" />
</form>
</div>
|
</li>
<li class="right">
<label class="theme-selector-label">
Theme
<select class="theme-selector" oninput="activateTheme(this.value)">
<option value="auto" selected>Auto</option>
<option value="light">Light</option>
<option value="dark">Dark</option>
</select>
</label> |</li>
</ul>
</div>
<div class="footer">
©
<a href="../copyright.html">
Copyright
</a>
2001-2025, Python Software Foundation.
<br />
This page is licensed under the Python Software Foundation License Version 2.
<br />
Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
<br />
See <a href="/license.html">History and License</a> for more information.<br />
<br />
The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>
<br />
<br />
Last updated on Apr 08, 2025 (14:33 UTC).
<a href="/bugs.html">Found a bug</a>?
<br />
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 8.2.3.
</div>
</body>
</html>