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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>16.3. time — Time access and conversions — Python 3.6.7 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.6.7 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="16.4. argparse — Parser for command-line options, arguments and sub-commands" href="argparse.html" /> <link rel="prev" title="16.2. io — Core tools for working with streams" href="io.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/time.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <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="argparse.html" title="16.4. argparse — Parser for command-line options, arguments and sub-commands" accesskey="N">next</a> |</li> <li class="right" > <a href="io.html" title="16.2. io — Core tools for working with streams" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 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="allos.html" accesskey="U">16. Generic Operating System Services</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-time"> <span id="time-time-access-and-conversions"></span><h1>16.3. <a class="reference internal" href="#module-time" title="time: Time access and conversions."><code class="xref py py-mod docutils literal notranslate"><span class="pre">time</span></code></a> — Time access and conversions<a class="headerlink" href="#module-time" title="Permalink to this headline">¶</a></h1> <hr class="docutils" /> <p>This module provides various time-related functions. For related functionality, see also the <a class="reference internal" href="datetime.html#module-datetime" title="datetime: Basic date and time types."><code class="xref py py-mod docutils literal notranslate"><span class="pre">datetime</span></code></a> and <a class="reference internal" href="calendar.html#module-calendar" title="calendar: Functions for working with calendars, including some emulation of the Unix cal program."><code class="xref py py-mod docutils literal notranslate"><span class="pre">calendar</span></code></a> modules.</p> <p>Although this module is always available, not all functions are available on all platforms. Most of the functions defined in this module call platform C library functions with the same name. It may sometimes be helpful to consult the platform documentation, because the semantics of these functions varies among platforms.</p> <p>An explanation of some terminology and conventions is in order.</p> <span class="target" id="epoch"></span><ul class="simple" id="index-0"> <li>The <em class="dfn">epoch</em> is the point where the time starts, and is platform dependent. For Unix, the epoch is January 1, 1970, 00:00:00 (UTC). To find out what the epoch is on a given platform, look at <code class="docutils literal notranslate"><span class="pre">time.gmtime(0)</span></code>.</li> </ul> <ul class="simple" id="index-1"> <li>The term <em class="dfn">seconds since the epoch</em> refers to the total number of elapsed seconds since the epoch, typically excluding <a class="reference external" href="https://en.wikipedia.org/wiki/Leap_second">leap seconds</a>. Leap seconds are excluded from this total on all POSIX-compliant platforms.</li> </ul> <ul class="simple" id="index-2"> <li>The functions in this module may not handle dates and times before the epoch or far in the future. The cut-off point in the future is determined by the C library; for 32-bit systems, it is typically in 2038.</li> </ul> <span id="index-3"></span><ul class="simple" id="time-y2kissues"> <li><strong>Year 2000 (Y2K) issues</strong>: Python depends on the platform’s C library, which generally doesn’t have year 2000 issues, since all dates and times are represented internally as seconds since the epoch. Function <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a> can parse 2-digit years when given <code class="docutils literal notranslate"><span class="pre">%y</span></code> format code. When 2-digit years are parsed, they are converted according to the POSIX and ISO C standards: values 69–99 are mapped to 1969–1999, and values 0–68 are mapped to 2000–2068.</li> </ul> <ul class="simple" id="index-4"> <li>UTC is Coordinated Universal Time (formerly known as Greenwich Mean Time, or GMT). The acronym UTC is not a mistake but a compromise between English and French.</li> </ul> <ul id="index-5"> <li><p class="first">DST is Daylight Saving Time, an adjustment of the timezone by (usually) one hour during part of the year. DST rules are magic (determined by local law) and can change from year to year. The C library has a table containing the local rules (often it is read from a system file for flexibility) and is the only source of True Wisdom in this respect.</p> </li> <li><p class="first">The precision of the various real-time functions may be less than suggested by the units in which their value or argument is expressed. E.g. on most Unix systems, the clock “ticks” only 50 or 100 times a second.</p> </li> <li><p class="first">On the other hand, the precision of <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> and <a class="reference internal" href="#time.sleep" title="time.sleep"><code class="xref py py-func docutils literal notranslate"><span class="pre">sleep()</span></code></a> is better than their Unix equivalents: times are expressed as floating point numbers, <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> returns the most accurate time available (using Unix <code class="xref c c-func docutils literal notranslate"><span class="pre">gettimeofday()</span></code> where available), and <a class="reference internal" href="#time.sleep" title="time.sleep"><code class="xref py py-func docutils literal notranslate"><span class="pre">sleep()</span></code></a> will accept a time with a nonzero fraction (Unix <code class="xref c c-func docutils literal notranslate"><span class="pre">select()</span></code> is used to implement this, where available).</p> </li> <li><p class="first">The time value as returned by <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a>, <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a>, and <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a>, and accepted by <a class="reference internal" href="#time.asctime" title="time.asctime"><code class="xref py py-func docutils literal notranslate"><span class="pre">asctime()</span></code></a>, <a class="reference internal" href="#time.mktime" title="time.mktime"><code class="xref py py-func docutils literal notranslate"><span class="pre">mktime()</span></code></a> and <a class="reference internal" href="#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strftime()</span></code></a>, is a sequence of 9 integers. The return values of <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a>, <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a>, and <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a> also offer attribute names for individual fields.</p> <p>See <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> for a description of these objects.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.3: </span>The <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> type was extended to provide the <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_gmtoff</span></code> and <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_zone</span></code> attributes when platform supports corresponding <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">tm</span></code> members.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.6: </span>The <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> attributes <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_gmtoff</span></code> and <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_zone</span></code> are now available on all platforms.</p> </div> </li> <li><p class="first">Use the following functions to convert between time representations:</p> <table border="1" class="docutils"> <colgroup> <col width="33%" /> <col width="33%" /> <col width="33%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">From</th> <th class="head">To</th> <th class="head">Use</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td>seconds since the epoch</td> <td><a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> in UTC</td> <td><a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a></td> </tr> <tr class="row-odd"><td>seconds since the epoch</td> <td><a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> in local time</td> <td><a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a></td> </tr> <tr class="row-even"><td><a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> in UTC</td> <td>seconds since the epoch</td> <td><a class="reference internal" href="calendar.html#calendar.timegm" title="calendar.timegm"><code class="xref py py-func docutils literal notranslate"><span class="pre">calendar.timegm()</span></code></a></td> </tr> <tr class="row-odd"><td><a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> in local time</td> <td>seconds since the epoch</td> <td><a class="reference internal" href="#time.mktime" title="time.mktime"><code class="xref py py-func docutils literal notranslate"><span class="pre">mktime()</span></code></a></td> </tr> </tbody> </table> </li> </ul> <div class="section" id="functions"> <span id="time-functions"></span><h2>16.3.1. Functions<a class="headerlink" href="#functions" title="Permalink to this headline">¶</a></h2> <dl class="function"> <dt id="time.asctime"> <code class="descclassname">time.</code><code class="descname">asctime</code><span class="sig-paren">(</span><span class="optional">[</span><em>t</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.asctime" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a tuple or <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> representing a time as returned by <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> or <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> to a string of the following form: <code class="docutils literal notranslate"><span class="pre">'Sun</span> <span class="pre">Jun</span> <span class="pre">20</span> <span class="pre">23:21:05</span> <span class="pre">1993'</span></code>. If <em>t</em> is not provided, the current time as returned by <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> is used. Locale information is not used by <a class="reference internal" href="#time.asctime" title="time.asctime"><code class="xref py py-func docutils literal notranslate"><span class="pre">asctime()</span></code></a>.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Unlike the C function of the same name, <a class="reference internal" href="#time.asctime" title="time.asctime"><code class="xref py py-func docutils literal notranslate"><span class="pre">asctime()</span></code></a> does not add a trailing newline.</p> </div> </dd></dl> <dl class="function"> <dt id="time.clock"> <code class="descclassname">time.</code><code class="descname">clock</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.clock" title="Permalink to this definition">¶</a></dt> <dd><p id="index-6">On Unix, return the current processor time as a floating point number expressed in seconds. The precision, and in fact the very definition of the meaning of “processor time”, depends on that of the C function of the same name.</p> <p>On Windows, this function returns wall-clock seconds elapsed since the first call to this function, as a floating point number, based on the Win32 function <code class="xref c c-func docutils literal notranslate"><span class="pre">QueryPerformanceCounter()</span></code>. The resolution is typically better than one microsecond.</p> <div class="deprecated"> <p><span class="versionmodified">Deprecated since version 3.3: </span>The behaviour of this function depends on the platform: use <a class="reference internal" href="#time.perf_counter" title="time.perf_counter"><code class="xref py py-func docutils literal notranslate"><span class="pre">perf_counter()</span></code></a> or <a class="reference internal" href="#time.process_time" title="time.process_time"><code class="xref py py-func docutils literal notranslate"><span class="pre">process_time()</span></code></a> instead, depending on your requirements, to have a well defined behaviour.</p> </div> </dd></dl> <dl class="function"> <dt id="time.clock_getres"> <code class="descclassname">time.</code><code class="descname">clock_getres</code><span class="sig-paren">(</span><em>clk_id</em><span class="sig-paren">)</span><a class="headerlink" href="#time.clock_getres" title="Permalink to this definition">¶</a></dt> <dd><p>Return the resolution (precision) of the specified clock <em>clk_id</em>. Refer to <a class="reference internal" href="#time-clock-id-constants"><span class="std std-ref">Clock ID Constants</span></a> for a list of accepted values for <em>clk_id</em>.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.clock_gettime"> <code class="descclassname">time.</code><code class="descname">clock_gettime</code><span class="sig-paren">(</span><em>clk_id</em><span class="sig-paren">)</span><a class="headerlink" href="#time.clock_gettime" title="Permalink to this definition">¶</a></dt> <dd><p>Return the time of the specified clock <em>clk_id</em>. Refer to <a class="reference internal" href="#time-clock-id-constants"><span class="std std-ref">Clock ID Constants</span></a> for a list of accepted values for <em>clk_id</em>.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.clock_settime"> <code class="descclassname">time.</code><code class="descname">clock_settime</code><span class="sig-paren">(</span><em>clk_id</em>, <em>time</em><span class="sig-paren">)</span><a class="headerlink" href="#time.clock_settime" title="Permalink to this definition">¶</a></dt> <dd><p>Set the time of the specified clock <em>clk_id</em>. Currently, <a class="reference internal" href="#time.CLOCK_REALTIME" title="time.CLOCK_REALTIME"><code class="xref py py-data docutils literal notranslate"><span class="pre">CLOCK_REALTIME</span></code></a> is the only accepted value for <em>clk_id</em>.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.ctime"> <code class="descclassname">time.</code><code class="descname">ctime</code><span class="sig-paren">(</span><span class="optional">[</span><em>secs</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.ctime" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a time expressed in seconds since the epoch to a string representing local time. If <em>secs</em> is not provided or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>, the current time as returned by <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> is used. <code class="docutils literal notranslate"><span class="pre">ctime(secs)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">asctime(localtime(secs))</span></code>. Locale information is not used by <a class="reference internal" href="#time.ctime" title="time.ctime"><code class="xref py py-func docutils literal notranslate"><span class="pre">ctime()</span></code></a>.</p> </dd></dl> <dl class="function"> <dt id="time.get_clock_info"> <code class="descclassname">time.</code><code class="descname">get_clock_info</code><span class="sig-paren">(</span><em>name</em><span class="sig-paren">)</span><a class="headerlink" href="#time.get_clock_info" title="Permalink to this definition">¶</a></dt> <dd><p>Get information on the specified clock as a namespace object. Supported clock names and the corresponding functions to read their value are:</p> <ul class="simple"> <li><code class="docutils literal notranslate"><span class="pre">'clock'</span></code>: <a class="reference internal" href="#time.clock" title="time.clock"><code class="xref py py-func docutils literal notranslate"><span class="pre">time.clock()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'monotonic'</span></code>: <a class="reference internal" href="#time.monotonic" title="time.monotonic"><code class="xref py py-func docutils literal notranslate"><span class="pre">time.monotonic()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'perf_counter'</span></code>: <a class="reference internal" href="#time.perf_counter" title="time.perf_counter"><code class="xref py py-func docutils literal notranslate"><span class="pre">time.perf_counter()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'process_time'</span></code>: <a class="reference internal" href="#time.process_time" title="time.process_time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time.process_time()</span></code></a></li> <li><code class="docutils literal notranslate"><span class="pre">'time'</span></code>: <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time.time()</span></code></a></li> </ul> <p>The result has the following attributes:</p> <ul class="simple"> <li><em>adjustable</em>: <code class="docutils literal notranslate"><span class="pre">True</span></code> if the clock can be changed automatically (e.g. by a NTP daemon) or manually by the system administrator, <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise</li> <li><em>implementation</em>: The name of the underlying C function used to get the clock value. Refer to <a class="reference internal" href="#time-clock-id-constants"><span class="std std-ref">Clock ID Constants</span></a> for possible values.</li> <li><em>monotonic</em>: <code class="docutils literal notranslate"><span class="pre">True</span></code> if the clock cannot go backward, <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise</li> <li><em>resolution</em>: The resolution of the clock in seconds (<a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a>)</li> </ul> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.gmtime"> <code class="descclassname">time.</code><code class="descname">gmtime</code><span class="sig-paren">(</span><span class="optional">[</span><em>secs</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.gmtime" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a time expressed in seconds since the epoch to a <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> in UTC in which the dst flag is always zero. If <em>secs</em> is not provided or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>, the current time as returned by <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> is used. Fractions of a second are ignored. See above for a description of the <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> object. See <a class="reference internal" href="calendar.html#calendar.timegm" title="calendar.timegm"><code class="xref py py-func docutils literal notranslate"><span class="pre">calendar.timegm()</span></code></a> for the inverse of this function.</p> </dd></dl> <dl class="function"> <dt id="time.localtime"> <code class="descclassname">time.</code><code class="descname">localtime</code><span class="sig-paren">(</span><span class="optional">[</span><em>secs</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.localtime" title="Permalink to this definition">¶</a></dt> <dd><p>Like <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> but converts to local time. If <em>secs</em> is not provided or <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>, the current time as returned by <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> is used. The dst flag is set to <code class="docutils literal notranslate"><span class="pre">1</span></code> when DST applies to the given time.</p> </dd></dl> <dl class="function"> <dt id="time.mktime"> <code class="descclassname">time.</code><code class="descname">mktime</code><span class="sig-paren">(</span><em>t</em><span class="sig-paren">)</span><a class="headerlink" href="#time.mktime" title="Permalink to this definition">¶</a></dt> <dd><p>This is the inverse function of <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a>. Its argument is the <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> or full 9-tuple (since the dst flag is needed; use <code class="docutils literal notranslate"><span class="pre">-1</span></code> as the dst flag if it is unknown) which expresses the time in <em>local</em> time, not UTC. It returns a floating point number, for compatibility with <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a>. If the input value cannot be represented as a valid time, either <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OverflowError</span></code></a> or <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> will be raised (which depends on whether the invalid value is caught by Python or the underlying C libraries). The earliest date for which it can generate a time is platform-dependent.</p> </dd></dl> <dl class="function"> <dt id="time.monotonic"> <code class="descclassname">time.</code><code class="descname">monotonic</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.monotonic" title="Permalink to this definition">¶</a></dt> <dd><p>Return the value (in fractional seconds) of a monotonic clock, i.e. a clock that cannot go backwards. The clock is not affected by system clock updates. The reference point of the returned value is undefined, so that only the difference between the results of consecutive calls is valid.</p> <p>On Windows versions older than Vista, <a class="reference internal" href="#time.monotonic" title="time.monotonic"><code class="xref py py-func docutils literal notranslate"><span class="pre">monotonic()</span></code></a> detects <code class="xref c c-func docutils literal notranslate"><span class="pre">GetTickCount()</span></code> integer overflow (32 bits, roll-over after 49.7 days). It increases an internal epoch (reference time) by 2<sup>32</sup> each time that an overflow is detected. The epoch is stored in the process-local state and so the value of <a class="reference internal" href="#time.monotonic" title="time.monotonic"><code class="xref py py-func docutils literal notranslate"><span class="pre">monotonic()</span></code></a> may be different in two Python processes running for more than 49 days. On more recent versions of Windows and on other operating systems, <a class="reference internal" href="#time.monotonic" title="time.monotonic"><code class="xref py py-func docutils literal notranslate"><span class="pre">monotonic()</span></code></a> is system-wide.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.5: </span>The function is now always available.</p> </div> </dd></dl> <dl class="function"> <dt id="time.perf_counter"> <code class="descclassname">time.</code><code class="descname">perf_counter</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.perf_counter" title="Permalink to this definition">¶</a></dt> <dd><p>Return the value (in fractional seconds) of a performance counter, i.e. a clock with the highest available resolution to measure a short duration. It does include time elapsed during sleep and is system-wide. The reference point of the returned value is undefined, so that only the difference between the results of consecutive calls is valid.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.process_time"> <code class="descclassname">time.</code><code class="descname">process_time</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.process_time" title="Permalink to this definition">¶</a></dt> <dd><p>Return the value (in fractional seconds) of the sum of the system and user CPU time of the current process. It does not include time elapsed during sleep. It is process-wide by definition. The reference point of the returned value is undefined, so that only the difference between the results of consecutive calls is valid.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="function"> <dt id="time.sleep"> <code class="descclassname">time.</code><code class="descname">sleep</code><span class="sig-paren">(</span><em>secs</em><span class="sig-paren">)</span><a class="headerlink" href="#time.sleep" title="Permalink to this definition">¶</a></dt> <dd><p>Suspend execution of the calling thread for the given number of seconds. The argument may be a floating point number to indicate a more precise sleep time. The actual suspension time may be less than that requested because any caught signal will terminate the <a class="reference internal" href="#time.sleep" title="time.sleep"><code class="xref py py-func docutils literal notranslate"><span class="pre">sleep()</span></code></a> following execution of that signal’s catching routine. Also, the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system.</p> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 3.5: </span>The function now sleeps at least <em>secs</em> even if the sleep is interrupted by a signal, except if the signal handler raises an exception (see <span class="target" id="index-7"></span><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0475"><strong>PEP 475</strong></a> for the rationale).</p> </div> </dd></dl> <dl class="function"> <dt id="time.strftime"> <code class="descclassname">time.</code><code class="descname">strftime</code><span class="sig-paren">(</span><em>format</em><span class="optional">[</span>, <em>t</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.strftime" title="Permalink to this definition">¶</a></dt> <dd><p>Convert a tuple or <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> representing a time as returned by <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> or <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> to a string as specified by the <em>format</em> argument. If <em>t</em> is not provided, the current time as returned by <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> is used. <em>format</em> must be a string. <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised if any field in <em>t</em> is outside of the allowed range.</p> <p>0 is a legal argument for any position in the time tuple; if it is normally illegal the value is forced to a correct one.</p> <p>The following directives can be embedded in the <em>format</em> string. They are shown without the optional field width and precision specification, and are replaced by the indicated characters in the <a class="reference internal" href="#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strftime()</span></code></a> result:</p> <table border="1" class="docutils"> <colgroup> <col width="17%" /> <col width="73%" /> <col width="11%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Directive</th> <th class="head">Meaning</th> <th class="head">Notes</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%a</span></code></td> <td>Locale’s abbreviated weekday name.</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%A</span></code></td> <td>Locale’s full weekday name.</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%b</span></code></td> <td>Locale’s abbreviated month name.</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%B</span></code></td> <td>Locale’s full month name.</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%c</span></code></td> <td>Locale’s appropriate date and time representation.</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%d</span></code></td> <td>Day of the month as a decimal number [01,31].</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%H</span></code></td> <td>Hour (24-hour clock) as a decimal number [00,23].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%I</span></code></td> <td>Hour (12-hour clock) as a decimal number [01,12].</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%j</span></code></td> <td>Day of the year as a decimal number [001,366].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%m</span></code></td> <td>Month as a decimal number [01,12].</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%M</span></code></td> <td>Minute as a decimal number [00,59].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%p</span></code></td> <td>Locale’s equivalent of either AM or PM.</td> <td>(1)</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%S</span></code></td> <td>Second as a decimal number [00,61].</td> <td>(2)</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%U</span></code></td> <td>Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.</td> <td>(3)</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%w</span></code></td> <td>Weekday as a decimal number [0(Sunday),6].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%W</span></code></td> <td>Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0.</td> <td>(3)</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%x</span></code></td> <td>Locale’s appropriate date representation.</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%X</span></code></td> <td>Locale’s appropriate time representation.</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%y</span></code></td> <td>Year without century as a decimal number [00,99].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%Y</span></code></td> <td>Year with century as a decimal number.</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%z</span></code></td> <td>Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59].</td> <td> </td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">%Z</span></code></td> <td>Time zone name (no characters if no time zone exists).</td> <td> </td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">%%</span></code></td> <td>A literal <code class="docutils literal notranslate"><span class="pre">'%'</span></code> character.</td> <td> </td> </tr> </tbody> </table> <p>Notes:</p> <ol class="arabic simple"> <li>When used with the <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a> function, the <code class="docutils literal notranslate"><span class="pre">%p</span></code> directive only affects the output hour field if the <code class="docutils literal notranslate"><span class="pre">%I</span></code> directive is used to parse the hour.</li> <li>The range really is <code class="docutils literal notranslate"><span class="pre">0</span></code> to <code class="docutils literal notranslate"><span class="pre">61</span></code>; value <code class="docutils literal notranslate"><span class="pre">60</span></code> is valid in timestamps representing <a class="reference external" href="https://en.wikipedia.org/wiki/Leap_second">leap seconds</a> and value <code class="docutils literal notranslate"><span class="pre">61</span></code> is supported for historical reasons.</li> <li>When used with the <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a> function, <code class="docutils literal notranslate"><span class="pre">%U</span></code> and <code class="docutils literal notranslate"><span class="pre">%W</span></code> are only used in calculations when the day of the week and the year are specified.</li> </ol> <p>Here is an example, a format for dates compatible with that specified in the <span class="target" id="index-8"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc2822.html"><strong>RFC 2822</strong></a> Internet email standard. <a class="footnote-reference" href="#id2" id="id1">[1]</a></p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">time</span> <span class="k">import</span> <span class="n">gmtime</span><span class="p">,</span> <span class="n">strftime</span> <span class="gp">>>> </span><span class="n">strftime</span><span class="p">(</span><span class="s2">"%a, </span><span class="si">%d</span><span class="s2"> %b %Y %H:%M:%S +0000"</span><span class="p">,</span> <span class="n">gmtime</span><span class="p">())</span> <span class="go">'Thu, 28 Jun 2001 14:17:15 +0000'</span> </pre></div> </div> <p>Additional directives may be supported on certain platforms, but only the ones listed here have a meaning standardized by ANSI C. To see the full set of format codes supported on your platform, consult the <em class="manpage">strftime(3)</em> documentation.</p> <p>On some platforms, an optional field width and precision specification can immediately follow the initial <code class="docutils literal notranslate"><span class="pre">'%'</span></code> of a directive in the following order; this is also not portable. The field width is normally 2 except for <code class="docutils literal notranslate"><span class="pre">%j</span></code> where it is 3.</p> </dd></dl> <dl class="function"> <dt id="time.strptime"> <code class="descclassname">time.</code><code class="descname">strptime</code><span class="sig-paren">(</span><em>string</em><span class="optional">[</span>, <em>format</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#time.strptime" title="Permalink to this definition">¶</a></dt> <dd><p>Parse a string representing a time according to a format. The return value is a <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> as returned by <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> or <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a>.</p> <p>The <em>format</em> parameter uses the same directives as those used by <a class="reference internal" href="#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strftime()</span></code></a>; it defaults to <code class="docutils literal notranslate"><span class="pre">"%a</span> <span class="pre">%b</span> <span class="pre">%d</span> <span class="pre">%H:%M:%S</span> <span class="pre">%Y"</span></code> which matches the formatting returned by <a class="reference internal" href="#time.ctime" title="time.ctime"><code class="xref py py-func docutils literal notranslate"><span class="pre">ctime()</span></code></a>. If <em>string</em> cannot be parsed according to <em>format</em>, or if it has excess data after parsing, <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised. The default values used to fill in any missing data when more accurate values cannot be inferred are <code class="docutils literal notranslate"><span class="pre">(1900,</span> <span class="pre">1,</span> <span class="pre">1,</span> <span class="pre">0,</span> <span class="pre">0,</span> <span class="pre">0,</span> <span class="pre">0,</span> <span class="pre">1,</span> <span class="pre">-1)</span></code>. Both <em>string</em> and <em>format</em> must be strings.</p> <p>For example:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">time</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">strptime</span><span class="p">(</span><span class="s2">"30 Nov 00"</span><span class="p">,</span> <span class="s2">"</span><span class="si">%d</span><span class="s2"> %b %y"</span><span class="p">)</span> <span class="go">time.struct_time(tm_year=2000, tm_mon=11, tm_mday=30, tm_hour=0, tm_min=0,</span> <span class="go"> tm_sec=0, tm_wday=3, tm_yday=335, tm_isdst=-1)</span> </pre></div> </div> <p>Support for the <code class="docutils literal notranslate"><span class="pre">%Z</span></code> directive is based on the values contained in <code class="docutils literal notranslate"><span class="pre">tzname</span></code> and whether <code class="docutils literal notranslate"><span class="pre">daylight</span></code> is true. Because of this, it is platform-specific except for recognizing UTC and GMT which are always known (and are considered to be non-daylight savings timezones).</p> <p>Only the directives specified in the documentation are supported. Because <code class="docutils literal notranslate"><span class="pre">strftime()</span></code> is implemented per platform it can sometimes offer more directives than those listed. But <code class="docutils literal notranslate"><span class="pre">strptime()</span></code> is independent of any platform and thus does not necessarily support all directives available that are not documented as supported.</p> </dd></dl> <dl class="class"> <dt id="time.struct_time"> <em class="property">class </em><code class="descclassname">time.</code><code class="descname">struct_time</code><a class="headerlink" href="#time.struct_time" title="Permalink to this definition">¶</a></dt> <dd><p>The type of the time value sequence returned by <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a>, <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a>, and <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a>. It is an object with a <a class="reference internal" href="../glossary.html#term-named-tuple"><span class="xref std std-term">named tuple</span></a> interface: values can be accessed by index and by attribute name. The following values are present:</p> <table border="1" class="docutils"> <colgroup> <col width="12%" /> <col width="32%" /> <col width="56%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Index</th> <th class="head">Attribute</th> <th class="head">Values</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td>0</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_year</span></code></td> <td>(for example, 1993)</td> </tr> <tr class="row-odd"><td>1</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_mon</span></code></td> <td>range [1, 12]</td> </tr> <tr class="row-even"><td>2</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_mday</span></code></td> <td>range [1, 31]</td> </tr> <tr class="row-odd"><td>3</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_hour</span></code></td> <td>range [0, 23]</td> </tr> <tr class="row-even"><td>4</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_min</span></code></td> <td>range [0, 59]</td> </tr> <tr class="row-odd"><td>5</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_sec</span></code></td> <td>range [0, 61]; see <strong>(2)</strong> in <a class="reference internal" href="#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strftime()</span></code></a> description</td> </tr> <tr class="row-even"><td>6</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_wday</span></code></td> <td>range [0, 6], Monday is 0</td> </tr> <tr class="row-odd"><td>7</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_yday</span></code></td> <td>range [1, 366]</td> </tr> <tr class="row-even"><td>8</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_isdst</span></code></td> <td>0, 1 or -1; see below</td> </tr> <tr class="row-odd"><td>N/A</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_zone</span></code></td> <td>abbreviation of timezone name</td> </tr> <tr class="row-even"><td>N/A</td> <td><code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_gmtoff</span></code></td> <td>offset east of UTC in seconds</td> </tr> </tbody> </table> <p>Note that unlike the C structure, the month value is a range of [1, 12], not [0, 11].</p> <p>In calls to <a class="reference internal" href="#time.mktime" title="time.mktime"><code class="xref py py-func docutils literal notranslate"><span class="pre">mktime()</span></code></a>, <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_isdst</span></code> may be set to 1 when daylight savings time is in effect, and 0 when it is not. A value of -1 indicates that this is not known, and will usually result in the correct state being filled in.</p> <p>When a tuple with an incorrect length is passed to a function expecting a <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a>, or having elements of the wrong type, a <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> is raised.</p> </dd></dl> <dl class="function"> <dt id="time.time"> <code class="descclassname">time.</code><code class="descname">time</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.time" title="Permalink to this definition">¶</a></dt> <dd><p>Return the time in seconds since the <a class="reference internal" href="#epoch">epoch</a> as a floating point number. The specific date of the epoch and the handling of <a class="reference external" href="https://en.wikipedia.org/wiki/Leap_second">leap seconds</a> is platform dependent. On Windows and most Unix systems, the epoch is January 1, 1970, 00:00:00 (UTC) and leap seconds are not counted towards the time in seconds since the epoch. This is commonly referred to as <a class="reference external" href="https://en.wikipedia.org/wiki/Unix_time">Unix time</a>. To find out what the epoch is on a given platform, look at <code class="docutils literal notranslate"><span class="pre">gmtime(0)</span></code>.</p> <p>Note that even though the time is always returned as a floating point number, not all systems provide time with a better precision than 1 second. While this function normally returns non-decreasing values, it can return a lower value than a previous call if the system clock has been set back between the two calls.</p> <p>The number returned by <a class="reference internal" href="#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate"><span class="pre">time()</span></code></a> may be converted into a more common time format (i.e. year, month, day, hour, etc…) in UTC by passing it to <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> function or in local time by passing it to the <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> function. In both cases a <a class="reference internal" href="#time.struct_time" title="time.struct_time"><code class="xref py py-class docutils literal notranslate"><span class="pre">struct_time</span></code></a> object is returned, from which the components of the calendar date may be accessed as attributes.</p> </dd></dl> <dl class="function"> <dt id="time.tzset"> <code class="descclassname">time.</code><code class="descname">tzset</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#time.tzset" title="Permalink to this definition">¶</a></dt> <dd><p>Resets the time conversion rules used by the library routines. The environment variable <span class="target" id="index-9"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">TZ</span></code> specifies how this is done.</p> <p>Availability: Unix.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p>Although in many cases, changing the <span class="target" id="index-10"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">TZ</span></code> environment variable may affect the output of functions like <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> without calling <a class="reference internal" href="#time.tzset" title="time.tzset"><code class="xref py py-func docutils literal notranslate"><span class="pre">tzset()</span></code></a>, this behavior should not be relied on.</p> <p class="last">The <span class="target" id="index-11"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">TZ</span></code> environment variable should contain no whitespace.</p> </div> <p>The standard format of the <span class="target" id="index-12"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">TZ</span></code> environment variable is (whitespace added for clarity):</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">std</span> <span class="n">offset</span> <span class="p">[</span><span class="n">dst</span> <span class="p">[</span><span class="n">offset</span> <span class="p">[,</span><span class="n">start</span><span class="p">[</span><span class="o">/</span><span class="n">time</span><span class="p">],</span> <span class="n">end</span><span class="p">[</span><span class="o">/</span><span class="n">time</span><span class="p">]]]]</span> </pre></div> </div> <p>Where the components are:</p> <dl class="docutils"> <dt><code class="docutils literal notranslate"><span class="pre">std</span></code> and <code class="docutils literal notranslate"><span class="pre">dst</span></code></dt> <dd>Three or more alphanumerics giving the timezone abbreviations. These will be propagated into time.tzname</dd> <dt><code class="docutils literal notranslate"><span class="pre">offset</span></code></dt> <dd>The offset has the form: <code class="docutils literal notranslate"><span class="pre">±</span> <span class="pre">hh[:mm[:ss]]</span></code>. This indicates the value added the local time to arrive at UTC. If preceded by a ‘-‘, the timezone is east of the Prime Meridian; otherwise, it is west. If no offset follows dst, summer time is assumed to be one hour ahead of standard time.</dd> <dt><code class="docutils literal notranslate"><span class="pre">start[/time],</span> <span class="pre">end[/time]</span></code></dt> <dd><p class="first">Indicates when to change to and back from DST. The format of the start and end dates are one of the following:</p> <dl class="docutils"> <dt><code class="samp docutils literal notranslate"><span class="pre">J</span><em><span class="pre">n</span></em></code></dt> <dd>The Julian day <em>n</em> (1 <= <em>n</em> <= 365). Leap days are not counted, so in all years February 28 is day 59 and March 1 is day 60.</dd> <dt><code class="samp docutils literal notranslate"><em><span class="pre">n</span></em></code></dt> <dd>The zero-based Julian day (0 <= <em>n</em> <= 365). Leap days are counted, and it is possible to refer to February 29.</dd> <dt><code class="samp docutils literal notranslate"><span class="pre">M</span><em><span class="pre">m</span></em><span class="pre">.</span><em><span class="pre">n</span></em><span class="pre">.</span><em><span class="pre">d</span></em></code></dt> <dd>The <em>d</em>’th day (0 <= <em>d</em> <= 6) of week <em>n</em> of month <em>m</em> of the year (1 <= <em>n</em> <= 5, 1 <= <em>m</em> <= 12, where week 5 means “the last <em>d</em> day in month <em>m</em>” which may occur in either the fourth or the fifth week). Week 1 is the first week in which the <em>d</em>’th day occurs. Day zero is a Sunday.</dd> </dl> <p class="last"><code class="docutils literal notranslate"><span class="pre">time</span></code> has the same format as <code class="docutils literal notranslate"><span class="pre">offset</span></code> except that no leading sign (‘-‘ or ‘+’) is allowed. The default, if time is not given, is 02:00:00.</p> </dd> </dl> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="p">[</span><span class="s1">'TZ'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'EST+05EDT,M4.1.0,M10.5.0'</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzset</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">strftime</span><span class="p">(</span><span class="s1">'</span><span class="si">%X</span><span class="s1"> </span><span class="si">%x</span><span class="s1"> %Z'</span><span class="p">)</span> <span class="go">'02:07:36 05/08/03 EDT'</span> <span class="gp">>>> </span><span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="p">[</span><span class="s1">'TZ'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'AEST-10AEDT-11,M10.5.0,M3.5.0'</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzset</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">strftime</span><span class="p">(</span><span class="s1">'</span><span class="si">%X</span><span class="s1"> </span><span class="si">%x</span><span class="s1"> %Z'</span><span class="p">)</span> <span class="go">'16:08:12 05/08/03 AEST'</span> </pre></div> </div> <p>On many Unix systems (including *BSD, Linux, Solaris, and Darwin), it is more convenient to use the system’s zoneinfo (<em class="manpage">tzfile(5)</em>) database to specify the timezone rules. To do this, set the <span class="target" id="index-13"></span><code class="xref std std-envvar docutils literal notranslate"><span class="pre">TZ</span></code> environment variable to the path of the required timezone datafile, relative to the root of the systems ‘zoneinfo’ timezone database, usually located at <code class="file docutils literal notranslate"><span class="pre">/usr/share/zoneinfo</span></code>. For example, <code class="docutils literal notranslate"><span class="pre">'US/Eastern'</span></code>, <code class="docutils literal notranslate"><span class="pre">'Australia/Melbourne'</span></code>, <code class="docutils literal notranslate"><span class="pre">'Egypt'</span></code> or <code class="docutils literal notranslate"><span class="pre">'Europe/Amsterdam'</span></code>.</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="p">[</span><span class="s1">'TZ'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'US/Eastern'</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzset</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzname</span> <span class="go">('EST', 'EDT')</span> <span class="gp">>>> </span><span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="p">[</span><span class="s1">'TZ'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'Egypt'</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzset</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">tzname</span> <span class="go">('EET', 'EEST')</span> </pre></div> </div> </dd></dl> </div> <div class="section" id="clock-id-constants"> <span id="time-clock-id-constants"></span><h2>16.3.2. Clock ID Constants<a class="headerlink" href="#clock-id-constants" title="Permalink to this headline">¶</a></h2> <p>These constants are used as parameters for <a class="reference internal" href="#time.clock_getres" title="time.clock_getres"><code class="xref py py-func docutils literal notranslate"><span class="pre">clock_getres()</span></code></a> and <a class="reference internal" href="#time.clock_gettime" title="time.clock_gettime"><code class="xref py py-func docutils literal notranslate"><span class="pre">clock_gettime()</span></code></a>.</p> <dl class="data"> <dt id="time.CLOCK_HIGHRES"> <code class="descclassname">time.</code><code class="descname">CLOCK_HIGHRES</code><a class="headerlink" href="#time.CLOCK_HIGHRES" title="Permalink to this definition">¶</a></dt> <dd><p>The Solaris OS has a <code class="docutils literal notranslate"><span class="pre">CLOCK_HIGHRES</span></code> timer that attempts to use an optimal hardware source, and may give close to nanosecond resolution. <code class="docutils literal notranslate"><span class="pre">CLOCK_HIGHRES</span></code> is the nonadjustable, high-resolution clock.</p> <p>Availability: Solaris.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="data"> <dt id="time.CLOCK_MONOTONIC"> <code class="descclassname">time.</code><code class="descname">CLOCK_MONOTONIC</code><a class="headerlink" href="#time.CLOCK_MONOTONIC" title="Permalink to this definition">¶</a></dt> <dd><p>Clock that cannot be set and represents monotonic time since some unspecified starting point.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="data"> <dt id="time.CLOCK_MONOTONIC_RAW"> <code class="descclassname">time.</code><code class="descname">CLOCK_MONOTONIC_RAW</code><a class="headerlink" href="#time.CLOCK_MONOTONIC_RAW" title="Permalink to this definition">¶</a></dt> <dd><p>Similar to <a class="reference internal" href="#time.CLOCK_MONOTONIC" title="time.CLOCK_MONOTONIC"><code class="xref py py-data docutils literal notranslate"><span class="pre">CLOCK_MONOTONIC</span></code></a>, but provides access to a raw hardware-based time that is not subject to NTP adjustments.</p> <p>Availability: Linux 2.6.28 or later.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="data"> <dt id="time.CLOCK_PROCESS_CPUTIME_ID"> <code class="descclassname">time.</code><code class="descname">CLOCK_PROCESS_CPUTIME_ID</code><a class="headerlink" href="#time.CLOCK_PROCESS_CPUTIME_ID" title="Permalink to this definition">¶</a></dt> <dd><p>High-resolution per-process timer from the CPU.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <dl class="data"> <dt id="time.CLOCK_THREAD_CPUTIME_ID"> <code class="descclassname">time.</code><code class="descname">CLOCK_THREAD_CPUTIME_ID</code><a class="headerlink" href="#time.CLOCK_THREAD_CPUTIME_ID" title="Permalink to this definition">¶</a></dt> <dd><p>Thread-specific CPU-time clock.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> <p>The following constant is the only parameter that can be sent to <a class="reference internal" href="#time.clock_settime" title="time.clock_settime"><code class="xref py py-func docutils literal notranslate"><span class="pre">clock_settime()</span></code></a>.</p> <dl class="data"> <dt id="time.CLOCK_REALTIME"> <code class="descclassname">time.</code><code class="descname">CLOCK_REALTIME</code><a class="headerlink" href="#time.CLOCK_REALTIME" title="Permalink to this definition">¶</a></dt> <dd><p>System-wide real-time clock. Setting this clock requires appropriate privileges.</p> <p>Availability: Unix.</p> <div class="versionadded"> <p><span class="versionmodified">New in version 3.3.</span></p> </div> </dd></dl> </div> <div class="section" id="timezone-constants"> <span id="time-timezone-constants"></span><h2>16.3.3. Timezone Constants<a class="headerlink" href="#timezone-constants" title="Permalink to this headline">¶</a></h2> <dl class="data"> <dt id="time.altzone"> <code class="descclassname">time.</code><code class="descname">altzone</code><a class="headerlink" href="#time.altzone" title="Permalink to this definition">¶</a></dt> <dd><p>The offset of the local DST timezone, in seconds west of UTC, if one is defined. This is negative if the local DST timezone is east of UTC (as in Western Europe, including the UK). Only use this if <code class="docutils literal notranslate"><span class="pre">daylight</span></code> is nonzero. See note below.</p> </dd></dl> <dl class="data"> <dt id="time.daylight"> <code class="descclassname">time.</code><code class="descname">daylight</code><a class="headerlink" href="#time.daylight" title="Permalink to this definition">¶</a></dt> <dd><p>Nonzero if a DST timezone is defined. See note below.</p> </dd></dl> <dl class="data"> <dt id="time.timezone"> <code class="descclassname">time.</code><code class="descname">timezone</code><a class="headerlink" href="#time.timezone" title="Permalink to this definition">¶</a></dt> <dd><p>The offset of the local (non-DST) timezone, in seconds west of UTC (negative in most of Western Europe, positive in the US, zero in the UK). See note below.</p> </dd></dl> <dl class="data"> <dt id="time.tzname"> <code class="descclassname">time.</code><code class="descname">tzname</code><a class="headerlink" href="#time.tzname" title="Permalink to this definition">¶</a></dt> <dd><p>A tuple of two strings: the first is the name of the local non-DST timezone, the second is the name of the local DST timezone. If no DST timezone is defined, the second string should not be used. See note below.</p> </dd></dl> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">For the above Timezone constants (<a class="reference internal" href="#time.altzone" title="time.altzone"><code class="xref py py-data docutils literal notranslate"><span class="pre">altzone</span></code></a>, <a class="reference internal" href="#time.daylight" title="time.daylight"><code class="xref py py-data docutils literal notranslate"><span class="pre">daylight</span></code></a>, <a class="reference internal" href="#time.timezone" title="time.timezone"><code class="xref py py-data docutils literal notranslate"><span class="pre">timezone</span></code></a>, and <a class="reference internal" href="#time.tzname" title="time.tzname"><code class="xref py py-data docutils literal notranslate"><span class="pre">tzname</span></code></a>), the value is determined by the timezone rules in effect at module load time or the last time <a class="reference internal" href="#time.tzset" title="time.tzset"><code class="xref py py-func docutils literal notranslate"><span class="pre">tzset()</span></code></a> is called and may be incorrect for times in the past. It is recommended to use the <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_gmtoff</span></code> and <code class="xref py py-attr docutils literal notranslate"><span class="pre">tm_zone</span></code> results from <a class="reference internal" href="#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">localtime()</span></code></a> to obtain timezone information.</p> </div> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt>Module <a class="reference internal" href="datetime.html#module-datetime" title="datetime: Basic date and time types."><code class="xref py py-mod docutils literal notranslate"><span class="pre">datetime</span></code></a></dt> <dd>More object-oriented interface to dates and times.</dd> <dt>Module <a class="reference internal" href="locale.html#module-locale" title="locale: Internationalization services."><code class="xref py py-mod docutils literal notranslate"><span class="pre">locale</span></code></a></dt> <dd>Internationalization services. The locale setting affects the interpretation of many format specifiers in <a class="reference internal" href="#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strftime()</span></code></a> and <a class="reference internal" href="#time.strptime" title="time.strptime"><code class="xref py py-func docutils literal notranslate"><span class="pre">strptime()</span></code></a>.</dd> <dt>Module <a class="reference internal" href="calendar.html#module-calendar" title="calendar: Functions for working with calendars, including some emulation of the Unix cal program."><code class="xref py py-mod docutils literal notranslate"><span class="pre">calendar</span></code></a></dt> <dd>General calendar-related functions. <a class="reference internal" href="calendar.html#calendar.timegm" title="calendar.timegm"><code class="xref py py-func docutils literal notranslate"><span class="pre">timegm()</span></code></a> is the inverse of <a class="reference internal" href="#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate"><span class="pre">gmtime()</span></code></a> from this module.</dd> </dl> </div> <p class="rubric">Footnotes</p> <table class="docutils footnote" frame="void" id="id2" rules="none"> <colgroup><col class="label" /><col /></colgroup> <tbody valign="top"> <tr><td class="label"><a class="fn-backref" href="#id1">[1]</a></td><td>The use of <code class="docutils literal notranslate"><span class="pre">%Z</span></code> is now deprecated, but the <code class="docutils literal notranslate"><span class="pre">%z</span></code> escape that expands to the preferred hour/minute offset is not supported by all ANSI C libraries. Also, a strict reading of the original 1982 <span class="target" id="index-14"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc822.html"><strong>RFC 822</strong></a> standard calls for a two-digit year (%y rather than %Y), but practice moved to 4-digit years long before the year 2000. After that, <span class="target" id="index-15"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc822.html"><strong>RFC 822</strong></a> became obsolete and the 4-digit year has been first recommended by <span class="target" id="index-16"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1123.html"><strong>RFC 1123</strong></a> and then mandated by <span class="target" id="index-17"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc2822.html"><strong>RFC 2822</strong></a>.</td></tr> </tbody> </table> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">16.3. <code class="docutils literal notranslate"><span class="pre">time</span></code> — Time access and conversions</a><ul> <li><a class="reference internal" href="#functions">16.3.1. Functions</a></li> <li><a class="reference internal" href="#clock-id-constants">16.3.2. Clock ID Constants</a></li> <li><a class="reference internal" href="#timezone-constants">16.3.3. Timezone Constants</a></li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="io.html" title="previous chapter">16.2. <code class="docutils literal notranslate"><span class="pre">io</span></code> — Core tools for working with streams</a></p> <h4>Next topic</h4> <p class="topless"><a href="argparse.html" title="next chapter">16.4. <code class="docutils literal notranslate"><span class="pre">argparse</span></code> — Parser for command-line options, arguments and sub-commands</a></p> <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/3.6/Doc/library/time.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <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="argparse.html" title="16.4. argparse — Parser for command-line options, arguments and sub-commands" >next</a> |</li> <li class="right" > <a href="io.html" title="16.2. io — Core tools for working with streams" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <a href="../index.html">3.6.7 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="allos.html" >16. 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