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<section id="module-gzip">
<span id="gzip-support-for-gzip-files"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">gzip</span></code> — Support for <strong class="program">gzip</strong> files<a class="headerlink" href="#module-gzip" 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/gzip.py">Lib/gzip.py</a></p>
<hr class="docutils" />
<p>This module provides a simple interface to compress and decompress files just
like the GNU programs <strong class="program">gzip</strong> and <strong class="program">gunzip</strong> would.</p>
<p>The data compression is provided by the <a class="reference internal" href="zlib.html#module-zlib" title="zlib: Low-level interface to compression and decompression routines compatible with gzip."><code class="xref py py-mod docutils literal notranslate"><span class="pre">zlib</span></code></a> module.</p>
<p>The <a class="reference internal" href="#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> module provides the <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> class, as well as the
<a class="reference internal" href="#gzip.open" title="gzip.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a>, <a class="reference internal" href="#gzip.compress" title="gzip.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">compress()</span></code></a> and <a class="reference internal" href="#gzip.decompress" title="gzip.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">decompress()</span></code></a> convenience functions.
The <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> class reads and writes <strong class="program">gzip</strong>-format files,
automatically compressing or decompressing the data so that it looks like an
ordinary <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>.</p>
<p>Note that additional file formats which can be decompressed by the
<strong class="program">gzip</strong> and <strong class="program">gunzip</strong> programs, such as those produced by
<strong class="program">compress</strong> and <strong class="program">pack</strong>, are not supported by this module.</p>
<p>The module defines the following items:</p>
<dl class="py function">
<dt class="sig sig-object py" id="gzip.open">
<span class="sig-prename descclassname"><span class="pre">gzip.</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="#gzip.open" title="Link to this definition"></a></dt>
<dd><p>Open a gzip-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>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">'a'</span></code>, <code class="docutils literal notranslate"><span class="pre">'ab'</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> or <code class="docutils literal notranslate"><span class="pre">'xb'</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">'at'</span></code>, <code class="docutils literal notranslate"><span class="pre">'wt'</span></code>, or <code class="docutils literal notranslate"><span class="pre">'xt'</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 0 to 9, as for the
<a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> constructor.</p>
<p>For binary mode, this function is equivalent to the <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a>
constructor: <code class="docutils literal notranslate"><span class="pre">GzipFile(filename,</span> <span class="pre">mode,</span> <span class="pre">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="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</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="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>Added support for <em>filename</em> being a file object, support for text mode,
and the <em>encoding</em>, <em>errors</em> and <em>newline</em> arguments.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.4: </span>Added support for the <code class="docutils literal notranslate"><span class="pre">'x'</span></code>, <code class="docutils literal notranslate"><span class="pre">'xb'</span></code> and <code class="docutils literal notranslate"><span class="pre">'xt'</span></code> modes.</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 exception">
<dt class="sig sig-object py" id="gzip.BadGzipFile">
<em class="property"><span class="k"><span class="pre">exception</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">gzip.</span></span><span class="sig-name descname"><span class="pre">BadGzipFile</span></span><a class="headerlink" href="#gzip.BadGzipFile" title="Link to this definition"></a></dt>
<dd><p>An exception raised for invalid gzip files. It inherits from <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.
<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> and <a class="reference internal" href="zlib.html#zlib.error" title="zlib.error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">zlib.error</span></code></a> can also be raised for invalid gzip
files.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.8.</span></p>
</div>
</dd></dl>
<dl class="py class">
<dt class="sig sig-object py" id="gzip.GzipFile">
<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">gzip.</span></span><span class="sig-name descname"><span class="pre">GzipFile</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">filename</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">mode</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">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">fileobj</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">mtime</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="#gzip.GzipFile" title="Link to this definition"></a></dt>
<dd><p>Constructor for the <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> class, which simulates most of the
methods of a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a>, with the exception of the <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>
method. At least one of <em>fileobj</em> and <em>filename</em> must be given a non-trivial
value.</p>
<p>The new class instance is based on <em>fileobj</em>, which can be a regular file, an
<a class="reference internal" href="io.html#io.BytesIO" title="io.BytesIO"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.BytesIO</span></code></a> object, or any other object which simulates a file. It
defaults to <code class="docutils literal notranslate"><span class="pre">None</span></code>, in which case <em>filename</em> is opened to provide a file
object.</p>
<p>When <em>fileobj</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, the <em>filename</em> argument is only used to be
included in the <strong class="program">gzip</strong> file header, which may include the original
filename of the uncompressed file. It defaults to the filename of <em>fileobj</em>, if
discernible; otherwise, it defaults to the empty string, and in this case the
original filename is not included in the header.</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">'a'</span></code>, <code class="docutils literal notranslate"><span class="pre">'ab'</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>, or <code class="docutils literal notranslate"><span class="pre">'xb'</span></code>, depending on whether the file will be read or
written. The default is the mode of <em>fileobj</em> if discernible; otherwise, the
default is <code class="docutils literal notranslate"><span class="pre">'rb'</span></code>. In future Python releases the mode of <em>fileobj</em> will
not be used. It is better to always specify <em>mode</em> for writing.</p>
<p>Note that the file is always opened in binary mode. To open a compressed file
in text mode, use <a class="reference internal" href="#gzip.open" title="gzip.open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> (or wrap your <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> with 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>).</p>
<p>The <em>compresslevel</em> argument is an integer from <code class="docutils literal notranslate"><span class="pre">0</span></code> to <code class="docutils literal notranslate"><span class="pre">9</span></code> controlling
the level of compression; <code class="docutils literal notranslate"><span class="pre">1</span></code> is fastest and produces the least
compression, and <code class="docutils literal notranslate"><span class="pre">9</span></code> is slowest and produces the most compression. <code class="docutils literal notranslate"><span class="pre">0</span></code>
is no compression. The default is <code class="docutils literal notranslate"><span class="pre">9</span></code>.</p>
<p>The optional <em>mtime</em> argument is the timestamp requested by gzip. The time
is in Unix format, i.e., seconds since 00:00:00 UTC, January 1, 1970.
If <em>mtime</em> is omitted or <code class="docutils literal notranslate"><span class="pre">None</span></code>, the current time is used. Use <em>mtime</em> = 0
to generate a compressed stream that does not depend on creation time.</p>
<p>See below for the <a class="reference internal" href="#gzip.GzipFile.mtime" title="gzip.GzipFile.mtime"><code class="xref py py-attr docutils literal notranslate"><span class="pre">mtime</span></code></a> attribute that is set when decompressing.</p>
<p>Calling a <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> objects <code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code> method does not close
<em>fileobj</em>, since you might wish to append more material after the compressed
data. This also allows you to pass an <a class="reference internal" href="io.html#io.BytesIO" title="io.BytesIO"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.BytesIO</span></code></a> object opened for
writing as <em>fileobj</em>, and retrieve the resulting memory buffer using the
<a class="reference internal" href="io.html#io.BytesIO" title="io.BytesIO"><code class="xref py py-class docutils literal notranslate"><span class="pre">io.BytesIO</span></code></a> objects <a class="reference internal" href="io.html#io.BytesIO.getvalue" title="io.BytesIO.getvalue"><code class="xref py py-meth docutils literal notranslate"><span class="pre">getvalue()</span></code></a> method.</p>
<p><a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> supports 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> interface,
including 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. Only the
<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> method isnt implemented.</p>
<p><a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> also provides the following method and attribute:</p>
<dl class="py method">
<dt class="sig sig-object py" id="gzip.GzipFile.peek">
<span class="sig-name descname"><span class="pre">peek</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">n</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#gzip.GzipFile.peek" title="Link to this definition"></a></dt>
<dd><p>Read <em>n</em> uncompressed bytes without advancing the file position.
At most one single read on the compressed stream is done to satisfy
the call. The number of bytes returned may be more or less than
requested.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>While calling <a class="reference internal" href="#gzip.GzipFile.peek" title="gzip.GzipFile.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="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a>, it may change the position of the underlying
file object (e.g. if the <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> was constructed with the
<em>fileobj</em> parameter).</p>
</div>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.2.</span></p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="gzip.GzipFile.mode">
<span class="sig-name descname"><span class="pre">mode</span></span><a class="headerlink" href="#gzip.GzipFile.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="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.13: </span>In previous versions it was an integer <code class="docutils literal notranslate"><span class="pre">1</span></code> or <code class="docutils literal notranslate"><span class="pre">2</span></code>.</p>
</div>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="gzip.GzipFile.mtime">
<span class="sig-name descname"><span class="pre">mtime</span></span><a class="headerlink" href="#gzip.GzipFile.mtime" title="Link to this definition"></a></dt>
<dd><p>When decompressing, this attribute is set to the last timestamp in the most
recently read header. It is an integer, holding the number of seconds
since the Unix epoch (00:00:00 UTC, January 1, 1970).
The initial value before reading any headers is <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
</dd></dl>
<dl class="py attribute">
<dt class="sig sig-object py" id="gzip.GzipFile.name">
<span class="sig-name descname"><span class="pre">name</span></span><a class="headerlink" href="#gzip.GzipFile.name" title="Link to this definition"></a></dt>
<dd><p>The path to the gzip file on disk, as 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>.
Equivalent to the output of <a class="reference internal" href="os.html#os.fspath" title="os.fspath"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.fspath()</span></code></a> on the original input path,
with no other normalization, resolution or expansion.</p>
</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, along with the
<em>mtime</em> constructor argument and <a class="reference internal" href="#gzip.GzipFile.mtime" title="gzip.GzipFile.mtime"><code class="xref py py-attr docutils literal notranslate"><span class="pre">mtime</span></code></a> attribute.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.2: </span>Support for zero-padded and unseekable files was added.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>The <a class="reference internal" href="io.html#io.BufferedIOBase.read1" title="io.BufferedIOBase.read1"><code class="xref py py-meth docutils literal notranslate"><span class="pre">io.BufferedIOBase.read1()</span></code></a> method is now implemented.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.4: </span>Added support for the <code class="docutils literal notranslate"><span class="pre">'x'</span></code> and <code class="docutils literal notranslate"><span class="pre">'xb'</span></code> modes.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.5: </span>Added support for writing arbitrary
<a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like objects</span></a>.
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="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.9: </span>Opening <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> for writing without specifying the <em>mode</em>
argument is deprecated.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span>Remove the <code class="docutils literal notranslate"><span class="pre">filename</span></code> attribute, use the <a class="reference internal" href="#gzip.GzipFile.name" title="gzip.GzipFile.name"><code class="xref py py-attr docutils literal notranslate"><span class="pre">name</span></code></a>
attribute instead.</p>
</div>
</dd></dl>
<dl class="py function">
<dt class="sig sig-object py" id="gzip.compress">
<span class="sig-prename descclassname"><span class="pre">gzip.</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>, <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">mtime</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="#gzip.compress" title="Link to this definition"></a></dt>
<dd><p>Compress the <em>data</em>, returning a <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 containing
the compressed data. <em>compresslevel</em> and <em>mtime</em> have the same meaning as in
the <a class="reference internal" href="#gzip.GzipFile" title="gzip.GzipFile"><code class="xref py py-class docutils literal notranslate"><span class="pre">GzipFile</span></code></a> constructor above.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.8: </span>Added the <em>mtime</em> parameter for reproducible output.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.11: </span>Speed is improved by compressing all data at once instead of in a
streamed fashion. Calls with <em>mtime</em> set to <code class="docutils literal notranslate"><span class="pre">0</span></code> are delegated to
<a class="reference internal" href="zlib.html#zlib.compress" title="zlib.compress"><code class="xref py py-func docutils literal notranslate"><span class="pre">zlib.compress()</span></code></a> for better speed. In this situation the
output may contain a gzip header “OS” byte value other than 255
“unknown” as supplied by the underlying zlib implementation.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.13: </span>The gzip header OS byte is guaranteed to be set to 255 when this function
is used as was the case in 3.10 and earlier.</p>
</div>
</dd></dl>
<dl class="py function">
<dt class="sig sig-object py" id="gzip.decompress">
<span class="sig-prename descclassname"><span class="pre">gzip.</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="#gzip.decompress" title="Link to this definition"></a></dt>
<dd><p>Decompress the <em>data</em>, returning a <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 containing the
uncompressed data. This function is capable of decompressing multi-member
gzip data (multiple gzip blocks concatenated together). When the data is
certain to contain only one member the <a class="reference internal" href="zlib.html#zlib.decompress" title="zlib.decompress"><code class="xref py py-func docutils literal notranslate"><span class="pre">zlib.decompress()</span></code></a> function with
<em>wbits</em> set to 31 is faster.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.2.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.11: </span>Speed is improved by decompressing members at once in memory instead of in
a streamed fashion.</p>
</div>
</dd></dl>
<section id="examples-of-usage">
<span id="gzip-usage-examples"></span><h2>Examples of usage<a class="headerlink" href="#examples-of-usage" title="Link to this heading"></a></h2>
<p>Example of how to read a compressed file:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">gzip</span>
<span class="k">with</span> <span class="n">gzip</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s1">&#39;/home/joe/file.txt.gz&#39;</span><span class="p">,</span> <span class="s1">&#39;rb&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
<span class="n">file_content</span> <span class="o">=</span> <span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
</pre></div>
</div>
<p>Example of how to create a compressed GZIP file:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">gzip</span>
<span class="n">content</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">&quot;Lots of content here&quot;</span>
<span class="k">with</span> <span class="n">gzip</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s1">&#39;/home/joe/file.txt.gz&#39;</span><span class="p">,</span> <span class="s1">&#39;wb&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
<span class="n">f</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">content</span><span class="p">)</span>
</pre></div>
</div>
<p>Example of how to GZIP compress an existing file:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">gzip</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">shutil</span>
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="s1">&#39;/home/joe/file.txt&#39;</span><span class="p">,</span> <span class="s1">&#39;rb&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f_in</span><span class="p">:</span>
<span class="k">with</span> <span class="n">gzip</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s1">&#39;/home/joe/file.txt.gz&#39;</span><span class="p">,</span> <span class="s1">&#39;wb&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">f_out</span><span class="p">:</span>
<span class="n">shutil</span><span class="o">.</span><span class="n">copyfileobj</span><span class="p">(</span><span class="n">f_in</span><span class="p">,</span> <span class="n">f_out</span><span class="p">)</span>
</pre></div>
</div>
<p>Example of how to GZIP compress a binary string:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span><span class="w"> </span><span class="nn">gzip</span>
<span class="n">s_in</span> <span class="o">=</span> <span class="sa">b</span><span class="s2">&quot;Lots of content here&quot;</span>
<span class="n">s_out</span> <span class="o">=</span> <span class="n">gzip</span><span class="o">.</span><span class="n">compress</span><span class="p">(</span><span class="n">s_in</span><span class="p">)</span>
</pre></div>
</div>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<dl class="simple">
<dt>Module <a class="reference internal" href="zlib.html#module-zlib" title="zlib: Low-level interface to compression and decompression routines compatible with gzip."><code class="xref py py-mod docutils literal notranslate"><span class="pre">zlib</span></code></a></dt><dd><p>The basic data compression module needed to support the <strong class="program">gzip</strong> file
format.</p>
</dd>
</dl>
</div>
</section>
<section id="command-line-interface">
<span id="gzip-cli"></span><h2>Command Line Interface<a class="headerlink" href="#command-line-interface" title="Link to this heading"></a></h2>
<p>The <a class="reference internal" href="#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> module provides a simple command line interface to compress or
decompress files.</p>
<p>Once executed the <a class="reference internal" href="#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> module keeps the input file(s).</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.8: </span>Add a new command line interface with a usage.
By default, when you will execute the CLI, the default compression level is 6.</p>
</div>
<section id="command-line-options">
<h3>Command line options<a class="headerlink" href="#command-line-options" title="Link to this heading"></a></h3>
<dl class="std option">
<dt class="sig sig-object std" id="cmdoption-gzip-arg-file">
<span class="sig-name descname"><span class="pre">file</span></span><span class="sig-prename descclassname"></span><a class="headerlink" href="#cmdoption-gzip-arg-file" title="Link to this definition"></a></dt>
<dd><p>If <em>file</em> is not specified, read from <a class="reference internal" href="sys.html#sys.stdin" title="sys.stdin"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stdin</span></code></a>.</p>
</dd></dl>
<dl class="std option">
<dt class="sig sig-object std" id="cmdoption-gzip-fast">
<span class="sig-name descname"><span class="pre">--fast</span></span><span class="sig-prename descclassname"></span><a class="headerlink" href="#cmdoption-gzip-fast" title="Link to this definition"></a></dt>
<dd><p>Indicates the fastest compression method (less compression).</p>
</dd></dl>
<dl class="std option">
<dt class="sig sig-object std" id="cmdoption-gzip-best">
<span class="sig-name descname"><span class="pre">--best</span></span><span class="sig-prename descclassname"></span><a class="headerlink" href="#cmdoption-gzip-best" title="Link to this definition"></a></dt>
<dd><p>Indicates the slowest compression method (best compression).</p>
</dd></dl>
<dl class="std option">
<dt class="sig sig-object std" id="cmdoption-gzip-d">
<span id="cmdoption-gzip-decompress"></span><span class="sig-name descname"><span class="pre">-d</span></span><span class="sig-prename descclassname"></span><span class="sig-prename descclassname"><span class="pre">,</span> </span><span class="sig-name descname"><span class="pre">--decompress</span></span><span class="sig-prename descclassname"></span><a class="headerlink" href="#cmdoption-gzip-d" title="Link to this definition"></a></dt>
<dd><p>Decompress the given file.</p>
</dd></dl>
<dl class="std option">
<dt class="sig sig-object std" id="cmdoption-gzip-h">
<span id="cmdoption-gzip-help"></span><span class="sig-name descname"><span class="pre">-h</span></span><span class="sig-prename descclassname"></span><span class="sig-prename descclassname"><span class="pre">,</span> </span><span class="sig-name descname"><span class="pre">--help</span></span><span class="sig-prename descclassname"></span><a class="headerlink" href="#cmdoption-gzip-h" title="Link to this definition"></a></dt>
<dd><p>Show the help message.</p>
</dd></dl>
</section>
</section>
</section>
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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">gzip</span></code> — Support for <strong class="program">gzip</strong> files</a><ul>
<li><a class="reference internal" href="#examples-of-usage">Examples of usage</a></li>
<li><a class="reference internal" href="#command-line-interface">Command Line Interface</a><ul>
<li><a class="reference internal" href="#command-line-options">Command line options</a></li>
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