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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">zoneinfo</span></code> — IANA time zone support</a><ul>
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<li><a class="reference internal" href="#using-zoneinfo">Using <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a></li>
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<li><a class="reference internal" href="#the-zoneinfo-class">The <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> class</a><ul>
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<section id="module-zoneinfo">
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<span id="zoneinfo-iana-time-zone-support"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">zoneinfo</span></code> — IANA time zone support<a class="headerlink" href="#module-zoneinfo" title="Link to this heading">¶</a></h1>
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<div class="versionadded">
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<p><span class="versionmodified added">Added in version 3.9.</span></p>
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<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Lib/zoneinfo">Lib/zoneinfo</a></p>
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<hr class="docutils" />
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<p>The <a class="reference internal" href="#module-zoneinfo" title="zoneinfo: IANA time zone support"><code class="xref py py-mod docutils literal notranslate"><span class="pre">zoneinfo</span></code></a> module provides a concrete time zone implementation to
|
||
support the IANA time zone database as originally specified in <span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-0615/"><strong>PEP 615</strong></a>. By
|
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default, <a class="reference internal" href="#module-zoneinfo" title="zoneinfo: IANA time zone support"><code class="xref py py-mod docutils literal notranslate"><span class="pre">zoneinfo</span></code></a> uses the system’s time zone data if available; if no
|
||
system time zone data is available, the library will fall back to using the
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first-party <a class="extlink-pypi reference external" href="https://pypi.org/project/tzdata/">tzdata</a> package available on PyPI.</p>
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<div class="admonition seealso">
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<p class="admonition-title">See also</p>
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<dl class="simple">
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<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><p>Provides the <a class="reference internal" href="datetime.html#datetime.time" title="datetime.time"><code class="xref py py-class docutils literal notranslate"><span class="pre">time</span></code></a> and <a class="reference internal" href="datetime.html#datetime.datetime" title="datetime.datetime"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime</span></code></a>
|
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types with which the <a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> class is designed to be used.</p>
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</dd>
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<dt>Package <a class="extlink-pypi reference external" href="https://pypi.org/project/tzdata/">tzdata</a></dt><dd><p>First-party package maintained by the CPython core developers to supply
|
||
time zone data via PyPI.</p>
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</dd>
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<p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>
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<p>This module does not work or is not available on WebAssembly. See
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<a class="reference internal" href="intro.html#wasm-availability"><span class="std std-ref">WebAssembly platforms</span></a> for more information.</p>
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<section id="using-zoneinfo">
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<h2>Using <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code><a class="headerlink" href="#using-zoneinfo" title="Link to this heading">¶</a></h2>
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||
<p><a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> is a concrete implementation of the <a class="reference internal" href="datetime.html#datetime.tzinfo" title="datetime.tzinfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.tzinfo</span></code></a>
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abstract base class, and is intended to be attached to <code class="docutils literal notranslate"><span class="pre">tzinfo</span></code>, either via
|
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the constructor, the <a class="reference internal" href="datetime.html#datetime.datetime.replace" title="datetime.datetime.replace"><code class="xref py py-meth docutils literal notranslate"><span class="pre">datetime.replace</span></code></a>
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method or <a class="reference internal" href="datetime.html#datetime.datetime.astimezone" title="datetime.datetime.astimezone"><code class="xref py py-meth docutils literal notranslate"><span class="pre">datetime.astimezone</span></code></a>:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span><span class="w"> </span><span class="nn">zoneinfo</span><span class="w"> </span><span class="kn">import</span> <span class="n">ZoneInfo</span>
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<span class="gp">>>> </span><span class="kn">from</span><span class="w"> </span><span class="nn">datetime</span><span class="w"> </span><span class="kn">import</span> <span class="n">datetime</span><span class="p">,</span> <span class="n">timedelta</span>
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<span class="gp">>>> </span><span class="n">dt</span> <span class="o">=</span> <span class="n">datetime</span><span class="p">(</span><span class="mi">2020</span><span class="p">,</span> <span class="mi">10</span><span class="p">,</span> <span class="mi">31</span><span class="p">,</span> <span class="mi">12</span><span class="p">,</span> <span class="n">tzinfo</span><span class="o">=</span><span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"America/Los_Angeles"</span><span class="p">))</span>
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<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">dt</span><span class="p">)</span>
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<span class="go">2020-10-31 12:00:00-07:00</span>
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<span class="gp">>>> </span><span class="n">dt</span><span class="o">.</span><span class="n">tzname</span><span class="p">()</span>
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<span class="go">'PDT'</span>
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</pre></div>
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</div>
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<p>Datetimes constructed in this way are compatible with datetime arithmetic and
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handle daylight saving time transitions with no further intervention:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">dt_add</span> <span class="o">=</span> <span class="n">dt</span> <span class="o">+</span> <span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span>
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<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">dt_add</span><span class="p">)</span>
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<span class="go">2020-11-01 12:00:00-08:00</span>
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<span class="gp">>>> </span><span class="n">dt_add</span><span class="o">.</span><span class="n">tzname</span><span class="p">()</span>
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<span class="go">'PST'</span>
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</pre></div>
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</div>
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<p>These time zones also support the <a class="reference internal" href="datetime.html#datetime.datetime.fold" title="datetime.datetime.fold"><code class="xref py py-attr docutils literal notranslate"><span class="pre">fold</span></code></a> attribute
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introduced in <span class="target" id="index-1"></span><a class="pep reference external" href="https://peps.python.org/pep-0495/"><strong>PEP 495</strong></a>. During offset transitions which induce ambiguous
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times (such as a daylight saving time to standard time transition), the offset
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from <em>before</em> the transition is used when <code class="docutils literal notranslate"><span class="pre">fold=0</span></code>, and the offset <em>after</em>
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||
the transition is used when <code class="docutils literal notranslate"><span class="pre">fold=1</span></code>, for example:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">dt</span> <span class="o">=</span> <span class="n">datetime</span><span class="p">(</span><span class="mi">2020</span><span class="p">,</span> <span class="mi">11</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="n">tzinfo</span><span class="o">=</span><span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"America/Los_Angeles"</span><span class="p">))</span>
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<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">dt</span><span class="p">)</span>
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<span class="go">2020-11-01 01:00:00-07:00</span>
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<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">dt</span><span class="o">.</span><span class="n">replace</span><span class="p">(</span><span class="n">fold</span><span class="o">=</span><span class="mi">1</span><span class="p">))</span>
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<span class="go">2020-11-01 01:00:00-08:00</span>
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</pre></div>
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</div>
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<p>When converting from another time zone, the fold will be set to the correct
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value:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span><span class="w"> </span><span class="nn">datetime</span><span class="w"> </span><span class="kn">import</span> <span class="n">timezone</span>
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<span class="gp">>>> </span><span class="n">LOS_ANGELES</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"America/Los_Angeles"</span><span class="p">)</span>
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<span class="gp">>>> </span><span class="n">dt_utc</span> <span class="o">=</span> <span class="n">datetime</span><span class="p">(</span><span class="mi">2020</span><span class="p">,</span> <span class="mi">11</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">8</span><span class="p">,</span> <span class="n">tzinfo</span><span class="o">=</span><span class="n">timezone</span><span class="o">.</span><span class="n">utc</span><span class="p">)</span>
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|
||
<span class="gp">>>> </span><span class="c1"># Before the PDT -> PST transition</span>
|
||
<span class="gp">>>> </span><span class="nb">print</span><span class="p">(</span><span class="n">dt_utc</span><span class="o">.</span><span class="n">astimezone</span><span class="p">(</span><span class="n">LOS_ANGELES</span><span class="p">))</span>
|
||
<span class="go">2020-11-01 01:00:00-07:00</span>
|
||
|
||
<span class="gp">>>> </span><span class="c1"># After the PDT -> PST transition</span>
|
||
<span class="gp">>>> </span><span class="nb">print</span><span class="p">((</span><span class="n">dt_utc</span> <span class="o">+</span> <span class="n">timedelta</span><span class="p">(</span><span class="n">hours</span><span class="o">=</span><span class="mi">1</span><span class="p">))</span><span class="o">.</span><span class="n">astimezone</span><span class="p">(</span><span class="n">LOS_ANGELES</span><span class="p">))</span>
|
||
<span class="go">2020-11-01 01:00:00-08:00</span>
|
||
</pre></div>
|
||
</div>
|
||
</section>
|
||
<section id="data-sources">
|
||
<h2>Data sources<a class="headerlink" href="#data-sources" title="Link to this heading">¶</a></h2>
|
||
<p>The <code class="docutils literal notranslate"><span class="pre">zoneinfo</span></code> module does not directly provide time zone data, and instead
|
||
pulls time zone information from the system time zone database or the
|
||
first-party PyPI package <a class="extlink-pypi reference external" href="https://pypi.org/project/tzdata/">tzdata</a>, if available. Some systems, including
|
||
notably Windows systems, do not have an IANA database available, and so for
|
||
projects targeting cross-platform compatibility that require time zone data, it
|
||
is recommended to declare a dependency on tzdata. If neither system data nor
|
||
tzdata are available, all calls to <a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> will raise
|
||
<a class="reference internal" href="#zoneinfo.ZoneInfoNotFoundError" title="zoneinfo.ZoneInfoNotFoundError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ZoneInfoNotFoundError</span></code></a>.</p>
|
||
<section id="configuring-the-data-sources">
|
||
<span id="zoneinfo-data-configuration"></span><h3>Configuring the data sources<a class="headerlink" href="#configuring-the-data-sources" title="Link to this heading">¶</a></h3>
|
||
<p>When <code class="docutils literal notranslate"><span class="pre">ZoneInfo(key)</span></code> is called, the constructor first searches the
|
||
directories specified in <a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> for a file matching <code class="docutils literal notranslate"><span class="pre">key</span></code>, and on
|
||
failure looks for a match in the tzdata package. This behavior can be
|
||
configured in three ways:</p>
|
||
<ol class="arabic simple">
|
||
<li><p>The default <a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> when not otherwise specified can be configured at
|
||
<a class="reference internal" href="#zoneinfo-data-compile-time-config"><span class="std std-ref">compile time</span></a>.</p></li>
|
||
<li><p><a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> can be configured using <a class="reference internal" href="#zoneinfo-data-environment-var"><span class="std std-ref">an environment variable</span></a>.</p></li>
|
||
<li><p>At <a class="reference internal" href="#zoneinfo-data-runtime-config"><span class="std std-ref">runtime</span></a>, the search path can be
|
||
manipulated using the <a class="reference internal" href="#zoneinfo.reset_tzpath" title="zoneinfo.reset_tzpath"><code class="xref py py-func docutils literal notranslate"><span class="pre">reset_tzpath()</span></code></a> function.</p></li>
|
||
</ol>
|
||
<section id="compile-time-configuration">
|
||
<span id="zoneinfo-data-compile-time-config"></span><h4>Compile-time configuration<a class="headerlink" href="#compile-time-configuration" title="Link to this heading">¶</a></h4>
|
||
<p>The default <a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> includes several common deployment locations for the
|
||
time zone database (except on Windows, where there are no “well-known”
|
||
locations for time zone data). On POSIX systems, downstream distributors and
|
||
those building Python from source who know where their system
|
||
time zone data is deployed may change the default time zone path by specifying
|
||
the compile-time option <code class="docutils literal notranslate"><span class="pre">TZPATH</span></code> (or, more likely, the <a class="reference internal" href="../using/configure.html#cmdoption-with-tzpath"><code class="xref std std-option docutils literal notranslate"><span class="pre">configure</span>
|
||
<span class="pre">flag</span> <span class="pre">--with-tzpath</span></code></a>), which should be a string delimited by
|
||
<a class="reference internal" href="os.html#os.pathsep" title="os.pathsep"><code class="xref py py-data docutils literal notranslate"><span class="pre">os.pathsep</span></code></a>.</p>
|
||
<p>On all platforms, the configured value is available as the <code class="docutils literal notranslate"><span class="pre">TZPATH</span></code> key in
|
||
<a class="reference internal" href="sysconfig.html#sysconfig.get_config_var" title="sysconfig.get_config_var"><code class="xref py py-func docutils literal notranslate"><span class="pre">sysconfig.get_config_var()</span></code></a>.</p>
|
||
</section>
|
||
<section id="environment-configuration">
|
||
<span id="zoneinfo-data-environment-var"></span><h4>Environment configuration<a class="headerlink" href="#environment-configuration" title="Link to this heading">¶</a></h4>
|
||
<p>When initializing <a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> (either at import time or whenever
|
||
<a class="reference internal" href="#zoneinfo.reset_tzpath" title="zoneinfo.reset_tzpath"><code class="xref py py-func docutils literal notranslate"><span class="pre">reset_tzpath()</span></code></a> is called with no arguments), the <code class="docutils literal notranslate"><span class="pre">zoneinfo</span></code> module will
|
||
use the environment variable <code class="docutils literal notranslate"><span class="pre">PYTHONTZPATH</span></code>, if it exists, to set the search
|
||
path.</p>
|
||
<dl class="std envvar">
|
||
<dt class="sig sig-object std" id="envvar-PYTHONTZPATH">
|
||
<span class="sig-name descname"><span class="pre">PYTHONTZPATH</span></span><a class="headerlink" href="#envvar-PYTHONTZPATH" title="Link to this definition">¶</a></dt>
|
||
<dd><p>This is an <a class="reference internal" href="os.html#os.pathsep" title="os.pathsep"><code class="xref py py-data docutils literal notranslate"><span class="pre">os.pathsep</span></code></a>-separated string containing the time zone
|
||
search path to use. It must consist of only absolute rather than relative
|
||
paths. Relative components specified in <code class="docutils literal notranslate"><span class="pre">PYTHONTZPATH</span></code> will not be used,
|
||
but otherwise the behavior when a relative path is specified is
|
||
implementation-defined; CPython will raise <a class="reference internal" href="#zoneinfo.InvalidTZPathWarning" title="zoneinfo.InvalidTZPathWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InvalidTZPathWarning</span></code></a>, but
|
||
other implementations are free to silently ignore the erroneous component
|
||
or raise an exception.</p>
|
||
</dd></dl>
|
||
|
||
<p>To set the system to ignore the system data and use the tzdata package
|
||
instead, set <code class="docutils literal notranslate"><span class="pre">PYTHONTZPATH=""</span></code>.</p>
|
||
</section>
|
||
<section id="runtime-configuration">
|
||
<span id="zoneinfo-data-runtime-config"></span><h4>Runtime configuration<a class="headerlink" href="#runtime-configuration" title="Link to this heading">¶</a></h4>
|
||
<p>The TZ search path can also be configured at runtime using the
|
||
<a class="reference internal" href="#zoneinfo.reset_tzpath" title="zoneinfo.reset_tzpath"><code class="xref py py-func docutils literal notranslate"><span class="pre">reset_tzpath()</span></code></a> function. This is generally not an advisable operation,
|
||
though it is reasonable to use it in test functions that require the use of a
|
||
specific time zone path (or require disabling access to the system time zones).</p>
|
||
</section>
|
||
</section>
|
||
</section>
|
||
<section id="the-zoneinfo-class">
|
||
<h2>The <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> class<a class="headerlink" href="#the-zoneinfo-class" title="Link to this heading">¶</a></h2>
|
||
<dl class="py class">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfo">
|
||
<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">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">ZoneInfo</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">key</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#zoneinfo.ZoneInfo" title="Link to this definition">¶</a></dt>
|
||
<dd><p>A concrete <a class="reference internal" href="datetime.html#datetime.tzinfo" title="datetime.tzinfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">datetime.tzinfo</span></code></a> subclass that represents an IANA time
|
||
zone specified by the string <code class="docutils literal notranslate"><span class="pre">key</span></code>. Calls to the primary constructor will
|
||
always return objects that compare identically; put another way, barring
|
||
cache invalidation via <a class="reference internal" href="#zoneinfo.ZoneInfo.clear_cache" title="zoneinfo.ZoneInfo.clear_cache"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ZoneInfo.clear_cache()</span></code></a>, for all values of
|
||
<code class="docutils literal notranslate"><span class="pre">key</span></code>, the following assertion will always be true:</p>
|
||
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">a</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="n">key</span><span class="p">)</span>
|
||
<span class="n">b</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="n">key</span><span class="p">)</span>
|
||
<span class="k">assert</span> <span class="n">a</span> <span class="ow">is</span> <span class="n">b</span>
|
||
</pre></div>
|
||
</div>
|
||
<p><code class="docutils literal notranslate"><span class="pre">key</span></code> must be in the form of a relative, normalized POSIX path, with no
|
||
up-level references. The constructor will raise <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> if a
|
||
non-conforming key is passed.</p>
|
||
<p>If no file matching <code class="docutils literal notranslate"><span class="pre">key</span></code> is found, the constructor will raise
|
||
<a class="reference internal" href="#zoneinfo.ZoneInfoNotFoundError" title="zoneinfo.ZoneInfoNotFoundError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ZoneInfoNotFoundError</span></code></a>.</p>
|
||
</dd></dl>
|
||
|
||
<p>The <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> class has two alternate constructors:</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfo.from_file">
|
||
<em class="property"><span class="k"><span class="pre">classmethod</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">ZoneInfo.</span></span><span class="sig-name descname"><span class="pre">from_file</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">fobj</span></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">key</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="#zoneinfo.ZoneInfo.from_file" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Constructs a <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> object from a file-like object returning bytes
|
||
(e.g. a file opened in binary mode or 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).
|
||
Unlike the primary constructor, this always constructs a new object.</p>
|
||
<p>The <code class="docutils literal notranslate"><span class="pre">key</span></code> parameter sets the name of the zone for the purposes of
|
||
<a class="reference internal" href="../reference/datamodel.html#object.__str__" title="object.__str__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__str__()</span></code></a> and <a class="reference internal" href="../reference/datamodel.html#object.__repr__" title="object.__repr__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__repr__()</span></code></a>.</p>
|
||
<p>Objects created via this constructor cannot be pickled (see <a class="reference internal" href="#pickling">pickling</a>).</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfo.no_cache">
|
||
<em class="property"><span class="k"><span class="pre">classmethod</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">ZoneInfo.</span></span><span class="sig-name descname"><span class="pre">no_cache</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">key</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#zoneinfo.ZoneInfo.no_cache" title="Link to this definition">¶</a></dt>
|
||
<dd><p>An alternate constructor that bypasses the constructor’s cache. It is
|
||
identical to the primary constructor, but returns a new object on each
|
||
call. This is most likely to be useful for testing or demonstration
|
||
purposes, but it can also be used to create a system with a different cache
|
||
invalidation strategy.</p>
|
||
<p>Objects created via this constructor will also bypass the cache of a
|
||
deserializing process when unpickled.</p>
|
||
<div class="admonition caution">
|
||
<p class="admonition-title">Caution</p>
|
||
<p>Using this constructor may change the semantics of your datetimes in
|
||
surprising ways, only use it if you know that you need to.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<p>The following class methods are also available:</p>
|
||
<dl class="py method">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfo.clear_cache">
|
||
<em class="property"><span class="k"><span class="pre">classmethod</span></span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">ZoneInfo.</span></span><span class="sig-name descname"><span class="pre">clear_cache</span></span><span class="sig-paren">(</span><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">only_keys</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="#zoneinfo.ZoneInfo.clear_cache" title="Link to this definition">¶</a></dt>
|
||
<dd><p>A method for invalidating the cache on the <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> class. If no
|
||
arguments are passed, all caches are invalidated and the next call to
|
||
the primary constructor for each key will return a new instance.</p>
|
||
<p>If an iterable of key names is passed to the <code class="docutils literal notranslate"><span class="pre">only_keys</span></code> parameter, only
|
||
the specified keys will be removed from the cache. Keys passed to
|
||
<code class="docutils literal notranslate"><span class="pre">only_keys</span></code> but not found in the cache are ignored.</p>
|
||
<div class="admonition warning">
|
||
<p class="admonition-title">Warning</p>
|
||
<p>Invoking this function may change the semantics of datetimes using
|
||
<code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> in surprising ways; this modifies module state
|
||
and thus may have wide-ranging effects. Only use it if you know that you
|
||
need to.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<p>The class has one attribute:</p>
|
||
<dl class="py attribute">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfo.key">
|
||
<span class="sig-prename descclassname"><span class="pre">ZoneInfo.</span></span><span class="sig-name descname"><span class="pre">key</span></span><a class="headerlink" href="#zoneinfo.ZoneInfo.key" title="Link to this definition">¶</a></dt>
|
||
<dd><p>This is a read-only <a class="reference internal" href="../glossary.html#term-attribute"><span class="xref std std-term">attribute</span></a> that returns the value of <code class="docutils literal notranslate"><span class="pre">key</span></code>
|
||
passed to the constructor, which should be a lookup key in the IANA time
|
||
zone database (e.g. <code class="docutils literal notranslate"><span class="pre">America/New_York</span></code>, <code class="docutils literal notranslate"><span class="pre">Europe/Paris</span></code> or
|
||
<code class="docutils literal notranslate"><span class="pre">Asia/Tokyo</span></code>).</p>
|
||
<p>For zones constructed from file without specifying a <code class="docutils literal notranslate"><span class="pre">key</span></code> parameter,
|
||
this will be set to <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>Although it is a somewhat common practice to expose these to end users,
|
||
these values are designed to be primary keys for representing the
|
||
relevant zones and not necessarily user-facing elements. Projects like
|
||
CLDR (the Unicode Common Locale Data Repository) can be used to get
|
||
more user-friendly strings from these keys.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<section id="string-representations">
|
||
<h3>String representations<a class="headerlink" href="#string-representations" title="Link to this heading">¶</a></h3>
|
||
<p>The string representation returned when calling <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> on a
|
||
<a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> object defaults to using the <a class="reference internal" href="#zoneinfo.ZoneInfo.key" title="zoneinfo.ZoneInfo.key"><code class="xref py py-attr docutils literal notranslate"><span class="pre">ZoneInfo.key</span></code></a> attribute (see
|
||
the note on usage in the attribute documentation):</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">zone</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"Pacific/Kwajalein"</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="nb">str</span><span class="p">(</span><span class="n">zone</span><span class="p">)</span>
|
||
<span class="go">'Pacific/Kwajalein'</span>
|
||
|
||
<span class="gp">>>> </span><span class="n">dt</span> <span class="o">=</span> <span class="n">datetime</span><span class="p">(</span><span class="mi">2020</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">15</span><span class="p">,</span> <span class="n">tzinfo</span><span class="o">=</span><span class="n">zone</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="sa">f</span><span class="s2">"</span><span class="si">{</span><span class="n">dt</span><span class="o">.</span><span class="n">isoformat</span><span class="p">()</span><span class="si">}</span><span class="s2"> [</span><span class="si">{</span><span class="n">dt</span><span class="o">.</span><span class="n">tzinfo</span><span class="si">}</span><span class="s2">]"</span>
|
||
<span class="go">'2020-04-01T03:15:00+12:00 [Pacific/Kwajalein]'</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>For objects constructed from a file without specifying a <code class="docutils literal notranslate"><span class="pre">key</span></code> parameter,
|
||
<code class="docutils literal notranslate"><span class="pre">str</span></code> falls back to calling <a class="reference internal" href="functions.html#repr" title="repr"><code class="xref py py-func docutils literal notranslate"><span class="pre">repr()</span></code></a>. <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code>’s <code class="docutils literal notranslate"><span class="pre">repr</span></code> is
|
||
implementation-defined and not necessarily stable between versions, but it is
|
||
guaranteed not to be a valid <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> key.</p>
|
||
</section>
|
||
<section id="pickle-serialization">
|
||
<span id="pickling"></span><h3>Pickle serialization<a class="headerlink" href="#pickle-serialization" title="Link to this heading">¶</a></h3>
|
||
<p>Rather than serializing all transition data, <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> objects are
|
||
serialized by key, and <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> objects constructed from files (even those
|
||
with a value for <code class="docutils literal notranslate"><span class="pre">key</span></code> specified) cannot be pickled.</p>
|
||
<p>The behavior of a <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> file depends on how it was constructed:</p>
|
||
<ol class="arabic">
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">ZoneInfo(key)</span></code>: When constructed with the primary constructor, a
|
||
<code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> object is serialized by key, and when deserialized, the
|
||
deserializing process uses the primary and thus it is expected that these
|
||
are expected to be the same object as other references to the same time
|
||
zone. For example, if <code class="docutils literal notranslate"><span class="pre">europe_berlin_pkl</span></code> is a string containing a pickle
|
||
constructed from <code class="docutils literal notranslate"><span class="pre">ZoneInfo("Europe/Berlin")</span></code>, one would expect the
|
||
following behavior:</p>
|
||
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">a</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"Europe/Berlin"</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="n">b</span> <span class="o">=</span> <span class="n">pickle</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="n">europe_berlin_pkl</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="n">a</span> <span class="ow">is</span> <span class="n">b</span>
|
||
<span class="go">True</span>
|
||
</pre></div>
|
||
</div>
|
||
</li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">ZoneInfo.no_cache(key)</span></code>: When constructed from the cache-bypassing
|
||
constructor, the <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> object is also serialized by key, but when
|
||
deserialized, the deserializing process uses the cache bypassing
|
||
constructor. If <code class="docutils literal notranslate"><span class="pre">europe_berlin_pkl_nc</span></code> is a string containing a pickle
|
||
constructed from <code class="docutils literal notranslate"><span class="pre">ZoneInfo.no_cache("Europe/Berlin")</span></code>, one would expect
|
||
the following behavior:</p>
|
||
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">a</span> <span class="o">=</span> <span class="n">ZoneInfo</span><span class="p">(</span><span class="s2">"Europe/Berlin"</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="n">b</span> <span class="o">=</span> <span class="n">pickle</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="n">europe_berlin_pkl_nc</span><span class="p">)</span>
|
||
<span class="gp">>>> </span><span class="n">a</span> <span class="ow">is</span> <span class="n">b</span>
|
||
<span class="go">False</span>
|
||
</pre></div>
|
||
</div>
|
||
</li>
|
||
<li><p><code class="docutils literal notranslate"><span class="pre">ZoneInfo.from_file(fobj,</span> <span class="pre">/,</span> <span class="pre">key=None)</span></code>: When constructed from a file, the
|
||
<code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> object raises an exception on pickling. If an end user wants to
|
||
pickle a <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> constructed from a file, it is recommended that they
|
||
use a wrapper type or a custom serialization function: either serializing by
|
||
key or storing the contents of the file object and serializing that.</p></li>
|
||
</ol>
|
||
<p>This method of serialization requires that the time zone data for the required
|
||
key be available on both the serializing and deserializing side, similar to the
|
||
way that references to classes and functions are expected to exist in both the
|
||
serializing and deserializing environments. It also means that no guarantees
|
||
are made about the consistency of results when unpickling a <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code>
|
||
pickled in an environment with a different version of the time zone data.</p>
|
||
</section>
|
||
</section>
|
||
<section id="functions">
|
||
<h2>Functions<a class="headerlink" href="#functions" title="Link to this heading">¶</a></h2>
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="zoneinfo.available_timezones">
|
||
<span class="sig-prename descclassname"><span class="pre">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">available_timezones</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#zoneinfo.available_timezones" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Get a set containing all the valid keys for IANA time zones available
|
||
anywhere on the time zone path. This is recalculated on every call to the
|
||
function.</p>
|
||
<p>This function only includes canonical zone names and does not include
|
||
“special” zones such as those under the <code class="docutils literal notranslate"><span class="pre">posix/</span></code> and <code class="docutils literal notranslate"><span class="pre">right/</span></code>
|
||
directories, or the <code class="docutils literal notranslate"><span class="pre">posixrules</span></code> zone.</p>
|
||
<div class="admonition caution">
|
||
<p class="admonition-title">Caution</p>
|
||
<p>This function may open a large number of files, as the best way to
|
||
determine if a file on the time zone path is a valid time zone is to
|
||
read the “magic string” at the beginning.</p>
|
||
</div>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>These values are not designed to be exposed to end-users; for user
|
||
facing elements, applications should use something like CLDR (the
|
||
Unicode Common Locale Data Repository) to get more user-friendly
|
||
strings. See also the cautionary note on <a class="reference internal" href="#zoneinfo.ZoneInfo.key" title="zoneinfo.ZoneInfo.key"><code class="xref py py-attr docutils literal notranslate"><span class="pre">ZoneInfo.key</span></code></a>.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="py function">
|
||
<dt class="sig sig-object py" id="zoneinfo.reset_tzpath">
|
||
<span class="sig-prename descclassname"><span class="pre">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">reset_tzpath</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">to</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="#zoneinfo.reset_tzpath" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Sets or resets the time zone search path (<a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a>) for the module.
|
||
When called with no arguments, <a class="reference internal" href="#zoneinfo.TZPATH" title="zoneinfo.TZPATH"><code class="xref py py-data docutils literal notranslate"><span class="pre">TZPATH</span></code></a> is set to the default value.</p>
|
||
<p>Calling <code class="docutils literal notranslate"><span class="pre">reset_tzpath</span></code> will not invalidate the <a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> cache,
|
||
and so calls to the primary <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> constructor will only use the new
|
||
<code class="docutils literal notranslate"><span class="pre">TZPATH</span></code> in the case of a cache miss.</p>
|
||
<p>The <code class="docutils literal notranslate"><span class="pre">to</span></code> parameter must be a <a class="reference internal" href="../glossary.html#term-sequence"><span class="xref std std-term">sequence</span></a> of strings or
|
||
<a class="reference internal" href="os.html#os.PathLike" title="os.PathLike"><code class="xref py py-class docutils literal notranslate"><span class="pre">os.PathLike</span></code></a> and not a string, all of which must be absolute paths.
|
||
<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 if something other than an absolute path
|
||
is passed.</p>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="globals">
|
||
<h2>Globals<a class="headerlink" href="#globals" title="Link to this heading">¶</a></h2>
|
||
<dl class="py data">
|
||
<dt class="sig sig-object py" id="zoneinfo.TZPATH">
|
||
<span class="sig-prename descclassname"><span class="pre">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">TZPATH</span></span><a class="headerlink" href="#zoneinfo.TZPATH" title="Link to this definition">¶</a></dt>
|
||
<dd><p>A read-only sequence representing the time zone search path – when
|
||
constructing a <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> from a key, the key is joined to each entry in
|
||
the <code class="docutils literal notranslate"><span class="pre">TZPATH</span></code>, and the first file found is used.</p>
|
||
<p><code class="docutils literal notranslate"><span class="pre">TZPATH</span></code> may contain only absolute paths, never relative paths,
|
||
regardless of how it is configured.</p>
|
||
<p>The object that <code class="docutils literal notranslate"><span class="pre">zoneinfo.TZPATH</span></code> points to may change in response to a
|
||
call to <a class="reference internal" href="#zoneinfo.reset_tzpath" title="zoneinfo.reset_tzpath"><code class="xref py py-func docutils literal notranslate"><span class="pre">reset_tzpath()</span></code></a>, so it is recommended to use
|
||
<code class="docutils literal notranslate"><span class="pre">zoneinfo.TZPATH</span></code> rather than importing <code class="docutils literal notranslate"><span class="pre">TZPATH</span></code> from <code class="docutils literal notranslate"><span class="pre">zoneinfo</span></code> or
|
||
assigning a long-lived variable to <code class="docutils literal notranslate"><span class="pre">zoneinfo.TZPATH</span></code>.</p>
|
||
<p>For more information on configuring the time zone search path, see
|
||
<a class="reference internal" href="#zoneinfo-data-configuration"><span class="std std-ref">Configuring the data sources</span></a>.</p>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
<section id="exceptions-and-warnings">
|
||
<h2>Exceptions and warnings<a class="headerlink" href="#exceptions-and-warnings" title="Link to this heading">¶</a></h2>
|
||
<dl class="py exception">
|
||
<dt class="sig sig-object py" id="zoneinfo.ZoneInfoNotFoundError">
|
||
<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">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">ZoneInfoNotFoundError</span></span><a class="headerlink" href="#zoneinfo.ZoneInfoNotFoundError" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Raised when construction of a <a class="reference internal" href="#zoneinfo.ZoneInfo" title="zoneinfo.ZoneInfo"><code class="xref py py-class docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a> object fails because the
|
||
specified key could not be found on the system. This is a subclass of
|
||
<a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a>.</p>
|
||
</dd></dl>
|
||
|
||
<dl class="py exception">
|
||
<dt class="sig sig-object py" id="zoneinfo.InvalidTZPathWarning">
|
||
<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">zoneinfo.</span></span><span class="sig-name descname"><span class="pre">InvalidTZPathWarning</span></span><a class="headerlink" href="#zoneinfo.InvalidTZPathWarning" title="Link to this definition">¶</a></dt>
|
||
<dd><p>Raised when <span class="target" id="index-2"></span><a class="reference internal" href="#envvar-PYTHONTZPATH"><code class="xref std std-envvar docutils literal notranslate"><span class="pre">PYTHONTZPATH</span></code></a> contains an invalid component that will
|
||
be filtered out, such as a relative path.</p>
|
||
</dd></dl>
|
||
|
||
</section>
|
||
</section>
|
||
|
||
|
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<div class="sphinxsidebarwrapper">
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<div>
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<h3><a href="../contents.html">Table of Contents</a></h3>
|
||
<ul>
|
||
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">zoneinfo</span></code> — IANA time zone support</a><ul>
|
||
<li><a class="reference internal" href="#using-zoneinfo">Using <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code></a></li>
|
||
<li><a class="reference internal" href="#data-sources">Data sources</a><ul>
|
||
<li><a class="reference internal" href="#configuring-the-data-sources">Configuring the data sources</a><ul>
|
||
<li><a class="reference internal" href="#compile-time-configuration">Compile-time configuration</a></li>
|
||
<li><a class="reference internal" href="#environment-configuration">Environment configuration</a></li>
|
||
<li><a class="reference internal" href="#runtime-configuration">Runtime configuration</a></li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
</li>
|
||
<li><a class="reference internal" href="#the-zoneinfo-class">The <code class="docutils literal notranslate"><span class="pre">ZoneInfo</span></code> class</a><ul>
|
||
<li><a class="reference internal" href="#string-representations">String representations</a></li>
|
||
<li><a class="reference internal" href="#pickle-serialization">Pickle serialization</a></li>
|
||
</ul>
|
||
</li>
|
||
<li><a class="reference internal" href="#functions">Functions</a></li>
|
||
<li><a class="reference internal" href="#globals">Globals</a></li>
|
||
<li><a class="reference internal" href="#exceptions-and-warnings">Exceptions and warnings</a></li>
|
||
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|
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|
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