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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> --- Decimal fixed-point and floating-point arithmetic</a><ul>
<li><a class="reference internal" href="#quick-start-tutorial">Quick-start tutorial</a></li>
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<li><a class="reference internal" href="#mitigating-round-off-error-with-increased-precision">Mitigating round-off error with increased precision</a></li>
<li><a class="reference internal" href="#special-values">Special values</a></li>
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<li><a class="reference internal" href="#working-with-threads">Working with threads</a></li>
<li><a class="reference internal" href="#recipes">Recipes</a></li>
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<section id="module-decimal">
<span id="decimal-decimal-fixed-point-and-floating-point-arithmetic"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> --- Decimal fixed-point and floating-point arithmetic<a class="headerlink" href="#module-decimal" title="Link to this heading">¶</a></h1>
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.14/Lib/decimal.py">Lib/decimal.py</a></p>
<hr class="docutils" />
<p>The <code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> module provides support for fast correctly rounded
decimal floating-point arithmetic. It offers several advantages over the
<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> datatype:</p>
<ul>
<li><p>Decimal "is based on a <a class="reference external" href="https://speleotrove.com/decimal/damodel.html#refnumber">floating-point model</a> which was designed
with people in mind, and necessarily has a paramount guiding principle --
computers must provide an arithmetic that works in the same way as the
arithmetic that people learn at school." -- excerpt from the decimal
arithmetic specification.</p></li>
<li><p>Decimal numbers can be represented exactly. In contrast, numbers like
<code class="docutils literal notranslate"><span class="pre">1.1</span></code> and <code class="docutils literal notranslate"><span class="pre">2.2</span></code> do not have exact representations in binary
floating point. End users typically would not expect <code class="docutils literal notranslate"><span class="pre">1.1</span> <span class="pre">+</span> <span class="pre">2.2</span></code> to display
as <code class="docutils literal notranslate"><span class="pre">3.3000000000000003</span></code> as it does with binary floating point.</p></li>
<li><p>The exactness carries over into arithmetic. In decimal floating point, <code class="docutils literal notranslate"><span class="pre">0.1</span>
<span class="pre">+</span> <span class="pre">0.1</span> <span class="pre">+</span> <span class="pre">0.1</span> <span class="pre">-</span> <span class="pre">0.3</span></code> is exactly equal to zero. In binary floating point, the result
is <code class="docutils literal notranslate"><span class="pre">5.5511151231257827e-017</span></code>. While near to zero, the differences
prevent reliable equality testing and differences can accumulate. For this
reason, decimal is preferred in accounting applications which have strict
equality invariants.</p></li>
<li><p>The decimal module incorporates a notion of significant places so that <code class="docutils literal notranslate"><span class="pre">1.30</span>
<span class="pre">+</span> <span class="pre">1.20</span></code> is <code class="docutils literal notranslate"><span class="pre">2.50</span></code>. The trailing zero is kept to indicate significance.
This is the customary presentation for monetary applications. For
multiplication, the "schoolbook" approach uses all the figures in the
multiplicands. For instance, <code class="docutils literal notranslate"><span class="pre">1.3</span> <span class="pre">*</span> <span class="pre">1.2</span></code> gives <code class="docutils literal notranslate"><span class="pre">1.56</span></code> while <code class="docutils literal notranslate"><span class="pre">1.30</span> <span class="pre">*</span>
<span class="pre">1.20</span></code> gives <code class="docutils literal notranslate"><span class="pre">1.5600</span></code>.</p></li>
<li><p>Unlike hardware based binary floating point, the decimal module has a user
alterable precision (defaulting to 28 places) which can be as large as needed for
a given problem:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">from</span><span class="w"> </span><span class="nn">decimal</span><span class="w"> </span><span class="kn">import</span> <span class="o">*</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">6</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">7</span><span class="p">)</span>
<span class="go">Decimal('0.142857')</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">28</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">7</span><span class="p">)</span>
<span class="go">Decimal('0.1428571428571428571428571429')</span>
</pre></div>
</div>
</li>
<li><p>Both binary and decimal floating point are implemented in terms of published
standards. While the built-in float type exposes only a modest portion of its
capabilities, the decimal module exposes all required parts of the standard.
When needed, the programmer has full control over rounding and signal handling.
This includes an option to enforce exact arithmetic by using exceptions
to block any inexact operations.</p></li>
<li><p>The decimal module was designed to support "without prejudice, both exact
unrounded decimal arithmetic (sometimes called fixed-point arithmetic)
and rounded floating-point arithmetic." -- excerpt from the decimal
arithmetic specification.</p></li>
</ul>
<p>The module design is centered around three concepts: the decimal number, the
context for arithmetic, and signals.</p>
<p>A decimal number is immutable. It has a sign, coefficient digits, and an
exponent. To preserve significance, the coefficient digits do not truncate
trailing zeros. Decimals also include special values such as
<code class="docutils literal notranslate"><span class="pre">Infinity</span></code>, <code class="docutils literal notranslate"><span class="pre">-Infinity</span></code>, and <code class="docutils literal notranslate"><span class="pre">NaN</span></code>. The standard also
differentiates <code class="docutils literal notranslate"><span class="pre">-0</span></code> from <code class="docutils literal notranslate"><span class="pre">+0</span></code>.</p>
<p>The context for arithmetic is an environment specifying precision, rounding
rules, limits on exponents, flags indicating the results of operations, and trap
enablers which determine whether signals are treated as exceptions. Rounding
options include <a class="reference internal" href="#decimal.ROUND_CEILING" title="decimal.ROUND_CEILING"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_CEILING</span></code></a>, <a class="reference internal" href="#decimal.ROUND_DOWN" title="decimal.ROUND_DOWN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_DOWN</span></code></a>,
<a class="reference internal" href="#decimal.ROUND_FLOOR" title="decimal.ROUND_FLOOR"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_FLOOR</span></code></a>, <a class="reference internal" href="#decimal.ROUND_HALF_DOWN" title="decimal.ROUND_HALF_DOWN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_DOWN</span></code></a>, <a class="reference internal" href="#decimal.ROUND_HALF_EVEN" title="decimal.ROUND_HALF_EVEN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_EVEN</span></code></a>,
<a class="reference internal" href="#decimal.ROUND_HALF_UP" title="decimal.ROUND_HALF_UP"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_UP</span></code></a>, <a class="reference internal" href="#decimal.ROUND_UP" title="decimal.ROUND_UP"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_UP</span></code></a>, and <a class="reference internal" href="#decimal.ROUND_05UP" title="decimal.ROUND_05UP"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_05UP</span></code></a>.</p>
<p>Signals are groups of exceptional conditions arising during the course of
computation. Depending on the needs of the application, signals may be ignored,
considered as informational, or treated as exceptions. The signals in the
decimal module are: <a class="reference internal" href="#decimal.Clamped" title="decimal.Clamped"><code class="xref py py-const docutils literal notranslate"><span class="pre">Clamped</span></code></a>, <a class="reference internal" href="#decimal.InvalidOperation" title="decimal.InvalidOperation"><code class="xref py py-const docutils literal notranslate"><span class="pre">InvalidOperation</span></code></a>,
<a class="reference internal" href="#decimal.DivisionByZero" title="decimal.DivisionByZero"><code class="xref py py-const docutils literal notranslate"><span class="pre">DivisionByZero</span></code></a>, <a class="reference internal" href="#decimal.Inexact" title="decimal.Inexact"><code class="xref py py-const docutils literal notranslate"><span class="pre">Inexact</span></code></a>, <a class="reference internal" href="#decimal.Rounded" title="decimal.Rounded"><code class="xref py py-const docutils literal notranslate"><span class="pre">Rounded</span></code></a>, <a class="reference internal" href="#decimal.Subnormal" title="decimal.Subnormal"><code class="xref py py-const docutils literal notranslate"><span class="pre">Subnormal</span></code></a>,
<a class="reference internal" href="#decimal.Overflow" title="decimal.Overflow"><code class="xref py py-const docutils literal notranslate"><span class="pre">Overflow</span></code></a>, <a class="reference internal" href="#decimal.Underflow" title="decimal.Underflow"><code class="xref py py-const docutils literal notranslate"><span class="pre">Underflow</span></code></a> and <a class="reference internal" href="#decimal.FloatOperation" title="decimal.FloatOperation"><code class="xref py py-const docutils literal notranslate"><span class="pre">FloatOperation</span></code></a>.</p>
<p>For each signal there is a flag and a trap enabler. When a signal is
encountered, its flag is set to one, then, if the trap enabler is
set to one, an exception is raised. Flags are sticky, so the user needs to
reset them before monitoring a calculation.</p>
<div class="admonition seealso">
<p class="admonition-title">همچنین ملاحظه نمائید</p>
<ul class="simple">
<li><p>IBM's General Decimal Arithmetic Specification, <a class="reference external" href="https://speleotrove.com/decimal/decarith.html">The General Decimal Arithmetic
Specification</a>.</p></li>
</ul>
</div>
<section id="quick-start-tutorial">
<span id="decimal-tutorial"></span><h2>Quick-start tutorial<a class="headerlink" href="#quick-start-tutorial" title="Link to this heading">¶</a></h2>
<p>The usual start to using decimals is importing the module, viewing the current
context with <a class="reference internal" href="#decimal.getcontext" title="decimal.getcontext"><code class="xref py py-func docutils literal notranslate"><span class="pre">getcontext()</span></code></a> and, if necessary, setting new values for
precision, rounding, or enabled traps:</p>
<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">decimal</span><span class="w"> </span><span class="kn">import</span> <span class="o">*</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span>
<span class="go">Context(prec=28, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,</span>
<span class="go"> capitals=1, clamp=0, flags=[], traps=[Overflow, DivisionByZero,</span>
<span class="go"> InvalidOperation])</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">7</span> <span class="c1"># Set a new precision</span>
</pre></div>
</div>
<p>Decimal instances can be constructed from integers, strings, floats, or tuples.
Construction from an integer or a float performs an exact conversion of the
value of that integer or float. Decimal numbers include special values such as
<code class="docutils literal notranslate"><span class="pre">NaN</span></code> which stands for "Not a number", positive and negative
<code class="docutils literal notranslate"><span class="pre">Infinity</span></code>, and <code class="docutils literal notranslate"><span class="pre">-0</span></code>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">28</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">10</span><span class="p">)</span>
<span class="go">Decimal('10')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.14'</span><span class="p">)</span>
<span class="go">Decimal('3.14')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mf">3.14</span><span class="p">)</span>
<span class="go">Decimal('3.140000000000000124344978758017532527446746826171875')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">((</span><span class="mi">0</span><span class="p">,</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">),</span> <span class="o">-</span><span class="mi">2</span><span class="p">))</span>
<span class="go">Decimal('3.14')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="mf">2.0</span> <span class="o">**</span> <span class="mf">0.5</span><span class="p">))</span>
<span class="go">Decimal('1.4142135623730951')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span> <span class="o">**</span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'0.5'</span><span class="p">)</span>
<span class="go">Decimal('1.414213562373095048801688724')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'NaN'</span><span class="p">)</span>
<span class="go">Decimal('NaN')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'-Infinity'</span><span class="p">)</span>
<span class="go">Decimal('-Infinity')</span>
</pre></div>
</div>
<p>If the <a class="reference internal" href="#decimal.FloatOperation" title="decimal.FloatOperation"><code class="xref py py-exc docutils literal notranslate"><span class="pre">FloatOperation</span></code></a> signal is trapped, accidental mixing of
decimals and floats in constructors or ordering comparisons raises
an exception:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">c</span> <span class="o">=</span> <span class="n">getcontext</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">c</span><span class="o">.</span><span class="n">traps</span><span class="p">[</span><span class="n">FloatOperation</span><span class="p">]</span> <span class="o">=</span> <span class="kc">True</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mf">3.14</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
File <span class="nb">"<stdin>"</span>, line <span class="m">1</span>, in <span class="n"><module></span>
<span class="gr">decimal.FloatOperation</span>: <span class="n">[<class 'decimal.FloatOperation'>]</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.5'</span><span class="p">)</span> <span class="o"><</span> <span class="mf">3.7</span>
<span class="gt">Traceback (most recent call last):</span>
File <span class="nb">"<stdin>"</span>, line <span class="m">1</span>, in <span class="n"><module></span>
<span class="gr">decimal.FloatOperation</span>: <span class="n">[<class 'decimal.FloatOperation'>]</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.5'</span><span class="p">)</span> <span class="o">==</span> <span class="mf">3.5</span>
<span class="go">True</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3.</span></p>
</div>
<p>The significance of a new Decimal is determined solely by the number of digits
input. Context precision and rounding only come into play during arithmetic
operations.</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">6</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.0'</span><span class="p">)</span>
<span class="go">Decimal('3.0')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.1415926535'</span><span class="p">)</span>
<span class="go">Decimal('3.1415926535')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.1415926535'</span><span class="p">)</span> <span class="o">+</span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.7182818285'</span><span class="p">)</span>
<span class="go">Decimal('5.85987')</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">rounding</span> <span class="o">=</span> <span class="n">ROUND_UP</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.1415926535'</span><span class="p">)</span> <span class="o">+</span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.7182818285'</span><span class="p">)</span>
<span class="go">Decimal('5.85988')</span>
</pre></div>
</div>
<p>If the internal limits of the C version are exceeded, constructing
a decimal raises <a class="reference internal" href="#decimal.InvalidOperation" title="decimal.InvalidOperation"><code class="xref py py-class docutils literal notranslate"><span class="pre">InvalidOperation</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s2">"1e9999999999999999999"</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
File <span class="nb">"<stdin>"</span>, line <span class="m">1</span>, in <span class="n"><module></span>
<span class="gr">decimal.InvalidOperation</span>: <span class="n">[<class 'decimal.InvalidOperation'>]</span>
</pre></div>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">تغییر داده شده در نسخه 3.3.</span></p>
</div>
<p>Decimals interact well with much of the rest of Python. Here is a small decimal
floating-point flying circus:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">data</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="n">Decimal</span><span class="p">,</span> <span class="s1">'1.34 1.87 3.45 2.35 1.00 0.03 9.25'</span><span class="o">.</span><span class="n">split</span><span class="p">()))</span>
<span class="gp">>>> </span><span class="nb">max</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="go">Decimal('9.25')</span>
<span class="gp">>>> </span><span class="nb">min</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="go">Decimal('0.03')</span>
<span class="gp">>>> </span><span class="nb">sorted</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="go">[Decimal('0.03'), Decimal('1.00'), Decimal('1.34'), Decimal('1.87'),</span>
<span class="go"> Decimal('2.35'), Decimal('3.45'), Decimal('9.25')]</span>
<span class="gp">>>> </span><span class="nb">sum</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>
<span class="go">Decimal('19.29')</span>
<span class="gp">>>> </span><span class="n">a</span><span class="p">,</span><span class="n">b</span><span class="p">,</span><span class="n">c</span> <span class="o">=</span> <span class="n">data</span><span class="p">[:</span><span class="mi">3</span><span class="p">]</span>
<span class="gp">>>> </span><span class="nb">str</span><span class="p">(</span><span class="n">a</span><span class="p">)</span>
<span class="go">'1.34'</span>
<span class="gp">>>> </span><span class="nb">float</span><span class="p">(</span><span class="n">a</span><span class="p">)</span>
<span class="go">1.34</span>
<span class="gp">>>> </span><span class="nb">round</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="go">Decimal('1.3')</span>
<span class="gp">>>> </span><span class="nb">int</span><span class="p">(</span><span class="n">a</span><span class="p">)</span>
<span class="go">1</span>
<span class="gp">>>> </span><span class="n">a</span> <span class="o">*</span> <span class="mi">5</span>
<span class="go">Decimal('6.70')</span>
<span class="gp">>>> </span><span class="n">a</span> <span class="o">*</span> <span class="n">b</span>
<span class="go">Decimal('2.5058')</span>
<span class="gp">>>> </span><span class="n">c</span> <span class="o">%</span> <span class="n">a</span>
<span class="go">Decimal('0.77')</span>
</pre></div>
</div>
<p>Decimals can be formatted (with <a class="reference internal" href="functions.html#format" title="format"><code class="xref py py-func docutils literal notranslate"><span class="pre">format()</span></code></a> built-in or <a class="reference internal" href="../reference/lexical_analysis.html#f-strings"><span class="std std-ref">f-strings</span></a>) in
fixed-point or scientific notation, using the same formatting syntax (see
<a class="reference internal" href="string.html#formatspec"><span class="std std-ref">Format specification mini-language</span></a>) as builtin <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> type:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="nb">format</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.675'</span><span class="p">),</span> <span class="s2">"f"</span><span class="p">)</span>
<span class="go">'2.675'</span>
<span class="gp">>>> </span><span class="nb">format</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.675'</span><span class="p">),</span> <span class="s2">".2f"</span><span class="p">)</span>
<span class="go">'2.68'</span>
<span class="gp">>>> </span><span class="sa">f</span><span class="s2">"</span><span class="si">{</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.675'</span><span class="p">)</span><span class="si">:</span><span class="s2">.2f</span><span class="si">}</span><span class="s2">"</span>
<span class="go">'2.68'</span>
<span class="gp">>>> </span><span class="nb">format</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.675'</span><span class="p">),</span> <span class="s2">".2e"</span><span class="p">)</span>
<span class="go">'2.68e+0'</span>
<span class="gp">>>> </span><span class="k">with</span> <span class="n">localcontext</span><span class="p">()</span> <span class="k">as</span> <span class="n">ctx</span><span class="p">:</span>
<span class="gp">... </span> <span class="n">ctx</span><span class="o">.</span><span class="n">rounding</span> <span class="o">=</span> <span class="n">ROUND_DOWN</span>
<span class="gp">... </span> <span class="nb">print</span><span class="p">(</span><span class="nb">format</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.675'</span><span class="p">),</span> <span class="s2">".2f"</span><span class="p">))</span>
<span class="gp">...</span>
<span class="go">2.67</span>
</pre></div>
</div>
<p>And some mathematical functions are also available to Decimal:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">prec</span> <span class="o">=</span> <span class="mi">28</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="o">.</span><span class="n">sqrt</span><span class="p">()</span>
<span class="go">Decimal('1.414213562373095048801688724')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span><span class="o">.</span><span class="n">exp</span><span class="p">()</span>
<span class="go">Decimal('2.718281828459045235360287471')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'10'</span><span class="p">)</span><span class="o">.</span><span class="n">ln</span><span class="p">()</span>
<span class="go">Decimal('2.302585092994045684017991455')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'10'</span><span class="p">)</span><span class="o">.</span><span class="n">log10</span><span class="p">()</span>
<span class="go">Decimal('1')</span>
</pre></div>
</div>
<p>The <a class="reference internal" href="#decimal.Decimal.quantize" title="decimal.Decimal.quantize"><code class="xref py py-meth docutils literal notranslate"><span class="pre">quantize()</span></code></a> method rounds a number to a fixed exponent. This method is
useful for monetary applications that often round results to a fixed number of
places:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'7.325'</span><span class="p">)</span><span class="o">.</span><span class="n">quantize</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'.01'</span><span class="p">),</span> <span class="n">rounding</span><span class="o">=</span><span class="n">ROUND_DOWN</span><span class="p">)</span>
<span class="go">Decimal('7.32')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'7.325'</span><span class="p">)</span><span class="o">.</span><span class="n">quantize</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'1.'</span><span class="p">),</span> <span class="n">rounding</span><span class="o">=</span><span class="n">ROUND_UP</span><span class="p">)</span>
<span class="go">Decimal('8')</span>
</pre></div>
</div>
<p>As shown above, the <a class="reference internal" href="#decimal.getcontext" title="decimal.getcontext"><code class="xref py py-func docutils literal notranslate"><span class="pre">getcontext()</span></code></a> function accesses the current context and
allows the settings to be changed. This approach meets the needs of most
applications.</p>
<p>For more advanced work, it may be useful to create alternate contexts using the
<a class="reference internal" href="#decimal.Context" title="decimal.Context"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Context()</span></code></a> constructor. To make an alternate active, use the <a class="reference internal" href="#decimal.setcontext" title="decimal.setcontext"><code class="xref py py-func docutils literal notranslate"><span class="pre">setcontext()</span></code></a>
function.</p>
<p>In accordance with the standard, the <code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> module provides two ready to
use standard contexts, <a class="reference internal" href="#decimal.BasicContext" title="decimal.BasicContext"><code class="xref py py-const docutils literal notranslate"><span class="pre">BasicContext</span></code></a> and <a class="reference internal" href="#decimal.ExtendedContext" title="decimal.ExtendedContext"><code class="xref py py-const docutils literal notranslate"><span class="pre">ExtendedContext</span></code></a>. The
former is especially useful for debugging because many of the traps are
enabled:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">myothercontext</span> <span class="o">=</span> <span class="n">Context</span><span class="p">(</span><span class="n">prec</span><span class="o">=</span><span class="mi">60</span><span class="p">,</span> <span class="n">rounding</span><span class="o">=</span><span class="n">ROUND_HALF_DOWN</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">setcontext</span><span class="p">(</span><span class="n">myothercontext</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">7</span><span class="p">)</span>
<span class="go">Decimal('0.142857142857142857142857142857142857142857142857142857142857')</span>
<span class="gp">>>> </span><span class="n">ExtendedContext</span>
<span class="go">Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,</span>
<span class="go"> capitals=1, clamp=0, flags=[], traps=[])</span>
<span class="gp">>>> </span><span class="n">setcontext</span><span class="p">(</span><span class="n">ExtendedContext</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">7</span><span class="p">)</span>
<span class="go">Decimal('0.142857143')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="go">Decimal('Infinity')</span>
<span class="gp">>>> </span><span class="n">setcontext</span><span class="p">(</span><span class="n">BasicContext</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
File <span class="nb">"<pyshell#143>"</span>, line <span class="m">1</span>, in <span class="n">-toplevel-</span>
<span class="w"> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="gr">DivisionByZero</span>: <span class="n">x / 0</span>
</pre></div>
</div>
<p>Contexts also have signal flags for monitoring exceptional conditions
encountered during computations. The flags remain set until explicitly cleared,
so it is best to clear the flags before each set of monitored computations by
using the <a class="reference internal" href="#decimal.Context.clear_flags" title="decimal.Context.clear_flags"><code class="xref py py-meth docutils literal notranslate"><span class="pre">clear_flags()</span></code></a> method.</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">setcontext</span><span class="p">(</span><span class="n">ExtendedContext</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">clear_flags</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">355</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">113</span><span class="p">)</span>
<span class="go">Decimal('3.14159292')</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span>
<span class="go">Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,</span>
<span class="go"> capitals=1, clamp=0, flags=[Inexact, Rounded], traps=[])</span>
</pre></div>
</div>
<p>The <em>flags</em> entry shows that the rational approximation to pi was
rounded (digits beyond the context precision were thrown away) and that the
result is inexact (some of the discarded digits were non-zero).</p>
<p>Individual traps are set using the dictionary in the <a class="reference internal" href="#decimal.Context.traps" title="decimal.Context.traps"><code class="xref py py-attr docutils literal notranslate"><span class="pre">traps</span></code></a>
attribute of a context:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">setcontext</span><span class="p">(</span><span class="n">ExtendedContext</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="go">Decimal('Infinity')</span>
<span class="gp">>>> </span><span class="n">getcontext</span><span class="p">()</span><span class="o">.</span><span class="n">traps</span><span class="p">[</span><span class="n">DivisionByZero</span><span class="p">]</span> <span class="o">=</span> <span class="mi">1</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="gt">Traceback (most recent call last):</span>
File <span class="nb">"<pyshell#112>"</span>, line <span class="m">1</span>, in <span class="n">-toplevel-</span>
<span class="w"> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="o">/</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
<span class="gr">DivisionByZero</span>: <span class="n">x / 0</span>
</pre></div>
</div>
<p>Most programs adjust the current context only once, at the beginning of the
program. And, in many applications, data is converted to <a class="reference internal" href="#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a> with
a single cast inside a loop. With context set and decimals created, the bulk of
the program manipulates the data no differently than with other Python numeric
types.</p>
</section>
<section id="decimal-objects">
<span id="decimal-decimal"></span><h2>Decimal objects<a class="headerlink" href="#decimal-objects" title="Link to this heading">¶</a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="decimal.Decimal">
<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">decimal.</span></span><span class="sig-name descname"><span class="pre">Decimal</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">value</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'0'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal" title="Link to this definition">¶</a></dt>
<dd><p>Construct a new <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> object based from <em>value</em>.</p>
<p><em>value</em> can be an integer, string, tuple, <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>, or another <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code>
object. If no <em>value</em> is given, returns <code class="docutils literal notranslate"><span class="pre">Decimal('0')</span></code>. If <em>value</em> is a
string, it should conform to the decimal numeric string syntax after leading
and trailing whitespace characters, as well as underscores throughout, are removed:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">sign</span> <span class="p">:</span><span class="o">:=</span> <span class="s1">'+'</span> <span class="o">|</span> <span class="s1">'-'</span>
<span class="n">digit</span> <span class="p">:</span><span class="o">:=</span> <span class="s1">'0'</span> <span class="o">|</span> <span class="s1">'1'</span> <span class="o">|</span> <span class="s1">'2'</span> <span class="o">|</span> <span class="s1">'3'</span> <span class="o">|</span> <span class="s1">'4'</span> <span class="o">|</span> <span class="s1">'5'</span> <span class="o">|</span> <span class="s1">'6'</span> <span class="o">|</span> <span class="s1">'7'</span> <span class="o">|</span> <span class="s1">'8'</span> <span class="o">|</span> <span class="s1">'9'</span>
<span class="n">indicator</span> <span class="p">:</span><span class="o">:=</span> <span class="s1">'e'</span> <span class="o">|</span> <span class="s1">'E'</span>
<span class="n">digits</span> <span class="p">:</span><span class="o">:=</span> <span class="n">digit</span> <span class="p">[</span><span class="n">digit</span><span class="p">]</span><span class="o">...</span>
<span class="n">decimal</span><span class="o">-</span><span class="n">part</span> <span class="p">:</span><span class="o">:=</span> <span class="n">digits</span> <span class="s1">'.'</span> <span class="p">[</span><span class="n">digits</span><span class="p">]</span> <span class="o">|</span> <span class="p">[</span><span class="s1">'.'</span><span class="p">]</span> <span class="n">digits</span>
<span class="n">exponent</span><span class="o">-</span><span class="n">part</span> <span class="p">:</span><span class="o">:=</span> <span class="n">indicator</span> <span class="p">[</span><span class="n">sign</span><span class="p">]</span> <span class="n">digits</span>
<span class="n">infinity</span> <span class="p">:</span><span class="o">:=</span> <span class="s1">'Infinity'</span> <span class="o">|</span> <span class="s1">'Inf'</span>
<span class="n">nan</span> <span class="p">:</span><span class="o">:=</span> <span class="s1">'NaN'</span> <span class="p">[</span><span class="n">digits</span><span class="p">]</span> <span class="o">|</span> <span class="s1">'sNaN'</span> <span class="p">[</span><span class="n">digits</span><span class="p">]</span>
<span class="n">numeric</span><span class="o">-</span><span class="n">value</span> <span class="p">:</span><span class="o">:=</span> <span class="n">decimal</span><span class="o">-</span><span class="n">part</span> <span class="p">[</span><span class="n">exponent</span><span class="o">-</span><span class="n">part</span><span class="p">]</span> <span class="o">|</span> <span class="n">infinity</span>
<span class="n">numeric</span><span class="o">-</span><span class="n">string</span> <span class="p">:</span><span class="o">:=</span> <span class="p">[</span><span class="n">sign</span><span class="p">]</span> <span class="n">numeric</span><span class="o">-</span><span class="n">value</span> <span class="o">|</span> <span class="p">[</span><span class="n">sign</span><span class="p">]</span> <span class="n">nan</span>
</pre></div>
</div>
<p>Other Unicode decimal digits are also permitted where <code class="docutils literal notranslate"><span class="pre">digit</span></code>
appears above. These include decimal digits from various other
alphabets (for example, Arabic-Indic and Devanāgarī digits) along
with the fullwidth digits <code class="docutils literal notranslate"><span class="pre">'\uff10'</span></code> through <code class="docutils literal notranslate"><span class="pre">'\uff19'</span></code>.
Case is not significant, so, for example, <code class="docutils literal notranslate"><span class="pre">inf</span></code>, <code class="docutils literal notranslate"><span class="pre">Inf</span></code>, <code class="docutils literal notranslate"><span class="pre">INFINITY</span></code>,
and <code class="docutils literal notranslate"><span class="pre">iNfINity</span></code> are all acceptable spellings for positive infinity.</p>
<p>If <em>value</em> is a <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate"><span class="pre">tuple</span></code></a>, it should have three components, a sign
(<code class="docutils literal notranslate"><span class="pre">0</span></code> for positive or <code class="docutils literal notranslate"><span class="pre">1</span></code> for negative), a <code class="xref py py-class docutils literal notranslate"><span class="pre">tuple</span></code> of
digits, and an integer exponent. For example, <code class="docutils literal notranslate"><span class="pre">Decimal((0,</span> <span class="pre">(1,</span> <span class="pre">4,</span> <span class="pre">1,</span> <span class="pre">4),</span> <span class="pre">-3))</span></code>
returns <code class="docutils literal notranslate"><span class="pre">Decimal('1.414')</span></code>.</p>
<p>If <em>value</em> is a <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>, the binary floating-point value is losslessly
converted to its exact decimal equivalent. This conversion can often require
53 or more digits of precision. For example, <code class="docutils literal notranslate"><span class="pre">Decimal(float('1.1'))</span></code>
converts to
<code class="docutils literal notranslate"><span class="pre">Decimal('1.100000000000000088817841970012523233890533447265625')</span></code>.</p>
<p>The <em>context</em> precision does not affect how many digits are stored. That is
determined exclusively by the number of digits in <em>value</em>. For example,
<code class="docutils literal notranslate"><span class="pre">Decimal('3.00000')</span></code> records all five zeros even if the context precision is
only three.</p>
<p>The purpose of the <em>context</em> argument is determining what to do if <em>value</em> is a
malformed string. If the context traps <a class="reference internal" href="#decimal.InvalidOperation" title="decimal.InvalidOperation"><code class="xref py py-const docutils literal notranslate"><span class="pre">InvalidOperation</span></code></a>, an exception
is raised; otherwise, the constructor returns a new Decimal with the value of
<code class="docutils literal notranslate"><span class="pre">NaN</span></code>.</p>
<p>Once constructed, <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> objects are immutable.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">تغییر داده شده در نسخه 3.2: </span>The argument to the constructor is now permitted to be a <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>
instance.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">تغییر داده شده در نسخه 3.3: </span><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> arguments raise an exception if the <a class="reference internal" href="#decimal.FloatOperation" title="decimal.FloatOperation"><code class="xref py py-exc docutils literal notranslate"><span class="pre">FloatOperation</span></code></a>
trap is set. By default the trap is off.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">تغییر داده شده در نسخه 3.6: </span>Underscores are allowed for grouping, as with integral and floating-point
literals in code.</p>
</div>
<p>Decimal floating-point objects share many properties with the other built-in
numeric types such as <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> and <a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>. All of the usual math
operations and special methods apply. Likewise, decimal objects can be
copied, pickled, printed, used as dictionary keys, used as set elements,
compared, sorted, and coerced to another type (such as <code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code> or
<code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code>).</p>
<p>There are some small differences between arithmetic on Decimal objects and
arithmetic on integers and floats. When the remainder operator <code class="docutils literal notranslate"><span class="pre">%</span></code> is
applied to Decimal objects, the sign of the result is the sign of the
<em>dividend</em> rather than the sign of the divisor:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="p">(</span><span class="o">-</span><span class="mi">7</span><span class="p">)</span> <span class="o">%</span> <span class="mi">4</span>
<span class="go">1</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="o">-</span><span class="mi">7</span><span class="p">)</span> <span class="o">%</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
<span class="go">Decimal('-3')</span>
</pre></div>
</div>
<p>The integer division operator <code class="docutils literal notranslate"><span class="pre">//</span></code> behaves analogously, returning the
integer part of the true quotient (truncating towards zero) rather than its
floor, so as to preserve the usual identity <code class="docutils literal notranslate"><span class="pre">x</span> <span class="pre">==</span> <span class="pre">(x</span> <span class="pre">//</span> <span class="pre">y)</span> <span class="pre">*</span> <span class="pre">y</span> <span class="pre">+</span> <span class="pre">x</span> <span class="pre">%</span> <span class="pre">y</span></code>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="o">-</span><span class="mi">7</span> <span class="o">//</span> <span class="mi">4</span>
<span class="go">-2</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="o">-</span><span class="mi">7</span><span class="p">)</span> <span class="o">//</span> <span class="n">Decimal</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span>
<span class="go">Decimal('-1')</span>
</pre></div>
</div>
<p>The <code class="docutils literal notranslate"><span class="pre">%</span></code> and <code class="docutils literal notranslate"><span class="pre">//</span></code> operators implement the <code class="docutils literal notranslate"><span class="pre">remainder</span></code> and
<code class="docutils literal notranslate"><span class="pre">divide-integer</span></code> operations (respectively) as described in the
specification.</p>
<p>Decimal objects cannot generally be combined with floats or
instances of <a class="reference internal" href="fractions.html#fractions.Fraction" title="fractions.Fraction"><code class="xref py py-class docutils literal notranslate"><span class="pre">fractions.Fraction</span></code></a> in arithmetic operations:
an attempt to add a <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> to a <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>, for
example, will raise 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>. However, it is possible to
use Python's comparison operators to compare a <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code>
instance <code class="docutils literal notranslate"><span class="pre">x</span></code> with another number <code class="docutils literal notranslate"><span class="pre">y</span></code>. This avoids confusing results
when doing equality comparisons between numbers of different types.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">تغییر داده شده در نسخه 3.2: </span>Mixed-type comparisons between <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instances and other
numeric types are now fully supported.</p>
</div>
<p>In addition to the standard numeric properties, decimal floating-point
objects also have a number of specialized methods:</p>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.adjusted">
<span class="sig-name descname"><span class="pre">adjusted</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.adjusted" title="Link to this definition">¶</a></dt>
<dd><p>Return the adjusted exponent after shifting out the coefficient's
rightmost digits until only the lead digit remains:
<code class="docutils literal notranslate"><span class="pre">Decimal('321e+5').adjusted()</span></code> returns seven. Used for determining the
position of the most significant digit with respect to the decimal point.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.as_integer_ratio">
<span class="sig-name descname"><span class="pre">as_integer_ratio</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.as_integer_ratio" title="Link to this definition">¶</a></dt>
<dd><p>Return a pair <code class="docutils literal notranslate"><span class="pre">(n,</span> <span class="pre">d)</span></code> of integers that represent the given
<code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instance as a fraction, in lowest terms and
with a positive denominator:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'-3.14'</span><span class="p">)</span><span class="o">.</span><span class="n">as_integer_ratio</span><span class="p">()</span>
<span class="go">(-157, 50)</span>
</pre></div>
</div>
<p>The conversion is exact. Raise OverflowError on infinities and ValueError
on NaNs.</p>
</dd></dl>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.6.</span></p>
</div>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.as_tuple">
<span class="sig-name descname"><span class="pre">as_tuple</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.as_tuple" title="Link to this definition">¶</a></dt>
<dd><p>Return a <a class="reference internal" href="../glossary.html#term-named-tuple"><span class="xref std std-term">named tuple</span></a> representation of the number:
<code class="docutils literal notranslate"><span class="pre">DecimalTuple(sign,</span> <span class="pre">digits,</span> <span class="pre">exponent)</span></code>.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.canonical">
<span class="sig-name descname"><span class="pre">canonical</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.canonical" title="Link to this definition">¶</a></dt>
<dd><p>Return the canonical encoding of the argument. Currently, the encoding of
a <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instance is always canonical, so this operation returns
its argument unchanged.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.compare">
<span class="sig-name descname"><span class="pre">compare</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.compare" title="Link to this definition">¶</a></dt>
<dd><p>Compare the values of two Decimal instances. <code class="xref py py-meth docutils literal notranslate"><span class="pre">compare()</span></code> returns a
Decimal instance, and if either operand is a NaN then the result is a
NaN:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">a</span> <span class="ow">or</span> <span class="n">b</span> <span class="ow">is</span> <span class="n">a</span> <span class="n">NaN</span> <span class="o">==></span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'NaN'</span><span class="p">)</span>
<span class="n">a</span> <span class="o"><</span> <span class="n">b</span> <span class="o">==></span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'-1'</span><span class="p">)</span>
<span class="n">a</span> <span class="o">==</span> <span class="n">b</span> <span class="o">==></span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'0'</span><span class="p">)</span>
<span class="n">a</span> <span class="o">></span> <span class="n">b</span> <span class="o">==></span> <span class="n">Decimal</span><span class="p">(</span><span class="s1">'1'</span><span class="p">)</span>
</pre></div>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.compare_signal">
<span class="sig-name descname"><span class="pre">compare_signal</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.compare_signal" title="Link to this definition">¶</a></dt>
<dd><p>This operation is identical to the <a class="reference internal" href="#decimal.Decimal.compare" title="decimal.Decimal.compare"><code class="xref py py-meth docutils literal notranslate"><span class="pre">compare()</span></code></a> method, except that all
NaNs signal. That is, if neither operand is a signaling NaN then any
quiet NaN operand is treated as though it were a signaling NaN.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.compare_total">
<span class="sig-name descname"><span class="pre">compare_total</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.compare_total" title="Link to this definition">¶</a></dt>
<dd><p>Compare two operands using their abstract representation rather than their
numerical value. Similar to the <a class="reference internal" href="#decimal.Decimal.compare" title="decimal.Decimal.compare"><code class="xref py py-meth docutils literal notranslate"><span class="pre">compare()</span></code></a> method, but the result
gives a total ordering on <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instances. Two
<code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instances with the same numeric value but different
representations compare unequal in this ordering:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'12.0'</span><span class="p">)</span><span class="o">.</span><span class="n">compare_total</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'12'</span><span class="p">))</span>
<span class="go">Decimal('-1')</span>
</pre></div>
</div>
<p>Quiet and signaling NaNs are also included in the total ordering. The
result of this function is <code class="docutils literal notranslate"><span class="pre">Decimal('0')</span></code> if both operands have the same
representation, <code class="docutils literal notranslate"><span class="pre">Decimal('-1')</span></code> if the first operand is lower in the
total order than the second, and <code class="docutils literal notranslate"><span class="pre">Decimal('1')</span></code> if the first operand is
higher in the total order than the second operand. See the specification
for details of the total order.</p>
<p>This operation is unaffected by context and is quiet: no flags are changed
and no rounding is performed. As an exception, the C version may raise
InvalidOperation if the second operand cannot be converted exactly.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.compare_total_mag">
<span class="sig-name descname"><span class="pre">compare_total_mag</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.compare_total_mag" title="Link to this definition">¶</a></dt>
<dd><p>Compare two operands using their abstract representation rather than their
value as in <a class="reference internal" href="#decimal.Decimal.compare_total" title="decimal.Decimal.compare_total"><code class="xref py py-meth docutils literal notranslate"><span class="pre">compare_total()</span></code></a>, but ignoring the sign of each operand.
<code class="docutils literal notranslate"><span class="pre">x.compare_total_mag(y)</span></code> is equivalent to
<code class="docutils literal notranslate"><span class="pre">x.copy_abs().compare_total(y.copy_abs())</span></code>.</p>
<p>This operation is unaffected by context and is quiet: no flags are changed
and no rounding is performed. As an exception, the C version may raise
InvalidOperation if the second operand cannot be converted exactly.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.conjugate">
<span class="sig-name descname"><span class="pre">conjugate</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.conjugate" title="Link to this definition">¶</a></dt>
<dd><p>Just returns self, this method is only to comply with the Decimal
Specification.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.copy_abs">
<span class="sig-name descname"><span class="pre">copy_abs</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.copy_abs" title="Link to this definition">¶</a></dt>
<dd><p>Return the absolute value of the argument. This operation is unaffected
by the context and is quiet: no flags are changed and no rounding is
performed.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.copy_negate">
<span class="sig-name descname"><span class="pre">copy_negate</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.copy_negate" title="Link to this definition">¶</a></dt>
<dd><p>Return the negation of the argument. This operation is unaffected by the
context and is quiet: no flags are changed and no rounding is performed.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.copy_sign">
<span class="sig-name descname"><span class="pre">copy_sign</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.copy_sign" title="Link to this definition">¶</a></dt>
<dd><p>Return a copy of the first operand with the sign set to be the same as the
sign of the second operand. For example:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'2.3'</span><span class="p">)</span><span class="o">.</span><span class="n">copy_sign</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'-1.5'</span><span class="p">))</span>
<span class="go">Decimal('-2.3')</span>
</pre></div>
</div>
<p>This operation is unaffected by context and is quiet: no flags are changed
and no rounding is performed. As an exception, the C version may raise
InvalidOperation if the second operand cannot be converted exactly.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.exp">
<span class="sig-name descname"><span class="pre">exp</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.exp" title="Link to this definition">¶</a></dt>
<dd><p>Return the value of the (natural) exponential function <code class="docutils literal notranslate"><span class="pre">e**x</span></code> at the
given number. The result is correctly rounded using the
<a class="reference internal" href="#decimal.ROUND_HALF_EVEN" title="decimal.ROUND_HALF_EVEN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_EVEN</span></code></a> rounding mode.</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span><span class="o">.</span><span class="n">exp</span><span class="p">()</span>
<span class="go">Decimal('2.718281828459045235360287471')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">321</span><span class="p">)</span><span class="o">.</span><span class="n">exp</span><span class="p">()</span>
<span class="go">Decimal('2.561702493119680037517373933E+139')</span>
</pre></div>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.from_float">
<em class="property"><span class="k"><span class="pre">classmethod</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">from_float</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">f</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><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.from_float" title="Link to this definition">¶</a></dt>
<dd><p>Alternative constructor that only accepts instances of <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> or
<a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>.</p>
<p>Note <code class="docutils literal notranslate"><span class="pre">Decimal.from_float(0.1)</span></code> is not the same as <code class="docutils literal notranslate"><span class="pre">Decimal('0.1')</span></code>.
Since 0.1 is not exactly representable in binary floating point, the
value is stored as the nearest representable value which is
<code class="docutils literal notranslate"><span class="pre">0x1.999999999999ap-4</span></code>. That equivalent value in decimal is
<code class="docutils literal notranslate"><span class="pre">0.1000000000000000055511151231257827021181583404541015625</span></code>.</p>
<div class="admonition note">
<p class="admonition-title">توجه</p>
<p>From Python 3.2 onwards, a <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instance
can also be constructed directly from a <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>.</p>
</div>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_float</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="go">Decimal('0.1000000000000000055511151231257827021181583404541015625')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_float</span><span class="p">(</span><span class="nb">float</span><span class="p">(</span><span class="s1">'nan'</span><span class="p">))</span>
<span class="go">Decimal('NaN')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_float</span><span class="p">(</span><span class="nb">float</span><span class="p">(</span><span class="s1">'inf'</span><span class="p">))</span>
<span class="go">Decimal('Infinity')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_float</span><span class="p">(</span><span class="nb">float</span><span class="p">(</span><span class="s1">'-inf'</span><span class="p">))</span>
<span class="go">Decimal('-Infinity')</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.1.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.from_number">
<em class="property"><span class="k"><span class="pre">classmethod</span></span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">from_number</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">number</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><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.from_number" title="Link to this definition">¶</a></dt>
<dd><p>Alternative constructor that only accepts instances of
<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>, <a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a> or <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code>, but not strings
or tuples.</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_number</span><span class="p">(</span><span class="mi">314</span><span class="p">)</span>
<span class="go">Decimal('314')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_number</span><span class="p">(</span><span class="mf">0.1</span><span class="p">)</span>
<span class="go">Decimal('0.1000000000000000055511151231257827021181583404541015625')</span>
<span class="gp">>>> </span><span class="n">Decimal</span><span class="o">.</span><span class="n">from_number</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s1">'3.14'</span><span class="p">))</span>
<span class="go">Decimal('3.14')</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.14.</span></p>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.fma">
<span class="sig-name descname"><span class="pre">fma</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">third</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.fma" title="Link to this definition">¶</a></dt>
<dd><p>Fused multiply-add. Return self*other+third with no rounding of the
intermediate product self*other.</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">Decimal</span><span class="p">(</span><span class="mi">2</span><span class="p">)</span><span class="o">.</span><span class="n">fma</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span>
<span class="go">Decimal('11')</span>
</pre></div>
</div>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_canonical">
<span class="sig-name descname"><span class="pre">is_canonical</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_canonical" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is canonical and <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a>
otherwise. Currently, a <code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instance is always canonical, so
this operation always returns <code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code>.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_finite">
<span class="sig-name descname"><span class="pre">is_finite</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_finite" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a finite number, and
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> if the argument is an infinity or a NaN.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_infinite">
<span class="sig-name descname"><span class="pre">is_infinite</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_infinite" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is either positive or negative
infinity and <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_nan">
<span class="sig-name descname"><span class="pre">is_nan</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_nan" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a (quiet or signaling) NaN and
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_normal">
<span class="sig-name descname"><span class="pre">is_normal</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.is_normal" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a <em>normal</em> finite number. Return
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> if the argument is zero, subnormal, infinite or a NaN.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_qnan">
<span class="sig-name descname"><span class="pre">is_qnan</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_qnan" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a quiet NaN, and
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_signed">
<span class="sig-name descname"><span class="pre">is_signed</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_signed" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument has a negative sign and
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> otherwise. Note that zeros and NaNs can both carry signs.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_snan">
<span class="sig-name descname"><span class="pre">is_snan</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_snan" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a signaling NaN and <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a>
otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_subnormal">
<span class="sig-name descname"><span class="pre">is_subnormal</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.is_subnormal" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is subnormal, and <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a>
otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.is_zero">
<span class="sig-name descname"><span class="pre">is_zero</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#decimal.Decimal.is_zero" title="Link to this definition">¶</a></dt>
<dd><p>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate"><span class="pre">True</span></code></a> if the argument is a (positive or negative) zero and
<a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate"><span class="pre">False</span></code></a> otherwise.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.ln">
<span class="sig-name descname"><span class="pre">ln</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.ln" title="Link to this definition">¶</a></dt>
<dd><p>Return the natural (base e) logarithm of the operand. The result is
correctly rounded using the <a class="reference internal" href="#decimal.ROUND_HALF_EVEN" title="decimal.ROUND_HALF_EVEN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_EVEN</span></code></a> rounding mode.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.log10">
<span class="sig-name descname"><span class="pre">log10</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.log10" title="Link to this definition">¶</a></dt>
<dd><p>Return the base ten logarithm of the operand. The result is correctly
rounded using the <a class="reference internal" href="#decimal.ROUND_HALF_EVEN" title="decimal.ROUND_HALF_EVEN"><code class="xref py py-const docutils literal notranslate"><span class="pre">ROUND_HALF_EVEN</span></code></a> rounding mode.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.logb">
<span class="sig-name descname"><span class="pre">logb</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.logb" title="Link to this definition">¶</a></dt>
<dd><p>For a nonzero number, return the adjusted exponent of its operand as a
<code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code> instance. If the operand is a zero then
<code class="docutils literal notranslate"><span class="pre">Decimal('-Infinity')</span></code> is returned and the <a class="reference internal" href="#decimal.DivisionByZero" title="decimal.DivisionByZero"><code class="xref py py-const docutils literal notranslate"><span class="pre">DivisionByZero</span></code></a> flag
is raised. If the operand is an infinity then <code class="docutils literal notranslate"><span class="pre">Decimal('Infinity')</span></code> is
returned.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.logical_and">
<span class="sig-name descname"><span class="pre">logical_and</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.logical_and" title="Link to this definition">¶</a></dt>
<dd><p><code class="xref py py-meth docutils literal notranslate"><span class="pre">logical_and()</span></code> is a logical operation which takes two <em>logical
operands</em> (see <a class="reference internal" href="#logical-operands-label"><span class="std std-ref">Logical operands</span></a>). The result is the
digit-wise <code class="docutils literal notranslate"><span class="pre">and</span></code> of the two operands.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.logical_invert">
<span class="sig-name descname"><span class="pre">logical_invert</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.logical_invert" title="Link to this definition">¶</a></dt>
<dd><p><code class="xref py py-meth docutils literal notranslate"><span class="pre">logical_invert()</span></code> is a logical operation. The
result is the digit-wise inversion of the operand.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.logical_or">
<span class="sig-name descname"><span class="pre">logical_or</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.logical_or" title="Link to this definition">¶</a></dt>
<dd><p><code class="xref py py-meth docutils literal notranslate"><span class="pre">logical_or()</span></code> is a logical operation which takes two <em>logical
operands</em> (see <a class="reference internal" href="#logical-operands-label"><span class="std std-ref">Logical operands</span></a>). The result is the
digit-wise <code class="docutils literal notranslate"><span class="pre">or</span></code> of the two operands.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.logical_xor">
<span class="sig-name descname"><span class="pre">logical_xor</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.logical_xor" title="Link to this definition">¶</a></dt>
<dd><p><code class="xref py py-meth docutils literal notranslate"><span class="pre">logical_xor()</span></code> is a logical operation which takes two <em>logical
operands</em> (see <a class="reference internal" href="#logical-operands-label"><span class="std std-ref">Logical operands</span></a>). The result is the
digit-wise exclusive or of the two operands.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.max">
<span class="sig-name descname"><span class="pre">max</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.max" title="Link to this definition">¶</a></dt>
<dd><p>Like <code class="docutils literal notranslate"><span class="pre">max(self,</span> <span class="pre">other)</span></code> except that the context rounding rule is applied
before returning and that <code class="docutils literal notranslate"><span class="pre">NaN</span></code> values are either signaled or
ignored (depending on the context and whether they are signaling or
quiet).</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.max_mag">
<span class="sig-name descname"><span class="pre">max_mag</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.max_mag" title="Link to this definition">¶</a></dt>
<dd><p>Similar to the <a class="reference internal" href="#decimal.Decimal.max" title="decimal.Decimal.max"><code class="xref py py-meth docutils literal notranslate"><span class="pre">max()</span></code></a> method, but the comparison is done using the
absolute values of the operands.</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.min">
<span class="sig-name descname"><span class="pre">min</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.min" title="Link to this definition">¶</a></dt>
<dd><p>Like <code class="docutils literal notranslate"><span class="pre">min(self,</span> <span class="pre">other)</span></code> except that the context rounding rule is applied
before returning and that <code class="docutils literal notranslate"><span class="pre">NaN</span></code> values are either signaled or
ignored (depending on the context and whether they are signaling or
quiet).</p>
</dd></dl>
<dl class="py method">
<dt class="sig sig-object py" id="decimal.Decimal.min_mag">
<span class="sig-name descname"><span class="pre">min_mag</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">other</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</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="#decimal.Decimal.min_mag" title="Link to this definition">¶</a></dt>
<dd><p>Similar to the <a class="reference internal" href="#decimal.Decimal.min" title="decimal.Decimal.min"><code class="xref py py-meth docutils literal notranslate"><span class="pre">min()</span></code></a> method, but the comparison is done using the
absolute values of the operands.</p>
</dd></dl>