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<section id="floating-point-objects">
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<span id="floatobjects"></span><h1>浮点数对象<a class="headerlink" href="#floating-point-objects" title="永久链接至标题">¶</a></h1>
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<span class="target" id="index-0"></span><dl class="type">
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<dt id="c.PyFloatObject">
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<code class="sig-name descname">PyFloatObject</code><a class="headerlink" href="#c.PyFloatObject" title="永久链接至目标">¶</a></dt>
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<dd><p>这个C类型 <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject</span></code></a> 的子类型代表一个Python浮点数对象。</p>
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</dd></dl>
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<dl class="var">
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<dt id="c.PyFloat_Type">
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<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <code class="sig-name descname">PyFloat_Type</code><a class="headerlink" href="#c.PyFloat_Type" title="永久链接至目标">¶</a></dt>
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<dd><p>这是个属于C类型 <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyTypeObject</span></code></a> 的代表Python浮点类型的实例。在Python层面的类型 <a class="reference internal" href="../library/functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a> 是同一个对象。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyFloat_Check">
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int <code class="sig-name descname">PyFloat_Check</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_Check" title="永久链接至目标">¶</a></dt>
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<dd><p>当他的参数是一个C类型 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a> 或者是C类型 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a> 的子类型时，返回真。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyFloat_CheckExact">
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int <code class="sig-name descname">PyFloat_CheckExact</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *p</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_CheckExact" title="永久链接至目标">¶</a></dt>
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<dd><p>当他的参数是一个C类型 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a> 但不是C类型 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a> 的子类型时，返回真。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyFloat_FromString">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyFloat_FromString</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *str</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_FromString" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: New reference.</em><p>根据字符串 <em>str</em> 的值创建一个 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a>，失败时返回 <code class="docutils literal notranslate"><span class="pre">NULL</span></code>。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyFloat_FromDouble">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyFloat_FromDouble</code><span class="sig-paren">(</span>double<em> v</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_FromDouble" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: New reference.</em><p>根据 <em>v</em> 创建一个 <a class="reference internal" href="#c.PyFloatObject" title="PyFloatObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyFloatObject</span></code></a> 对象，失败时返回 <code class="docutils literal notranslate"><span class="pre">NULL</span></code>。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyFloat_AsDouble">
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double <code class="sig-name descname">PyFloat_AsDouble</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *pyfloat</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_AsDouble" title="永久链接至目标">¶</a></dt>
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<dd><p>返回一个 C <code class="xref c c-type docutils literal notranslate"><span class="pre">double</span></code> 代表 <em>pyfloat</em> 的内容。 如果 <em>pyfloat</em> 不是一个 Python 浮点数对象但是具有 <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__float__()</span></code></a> 方法，此方法将首先被调用，将 <em>pyfloat</em> 转换成一个数点数。 如果 <code class="docutils literal notranslate"><span class="pre">__float__()</span></code> 未定义则将回退至 <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__index__()</span></code></a>。 如果失败，此方法将返回 <code class="docutils literal notranslate"><span class="pre">-1.0</span></code>，因此开发者应当调用 <a class="reference internal" href="exceptions.html#c.PyErr_Occurred" title="PyErr_Occurred"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyErr_Occurred()</span></code></a> 来检查错误。</p>
|
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<div class="versionchanged">
|
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<p><span class="versionmodified changed">在 3.8 版更改: </span>如果可用将使用 <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__index__()</span></code></a>。</p>
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</div>
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</dd></dl>
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<dl class="function">
|
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<dt id="c.PyFloat_AS_DOUBLE">
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double <code class="sig-name descname">PyFloat_AS_DOUBLE</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *pyfloat</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_AS_DOUBLE" title="永久链接至目标">¶</a></dt>
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<dd><p>返回一个 <em>pyfloat</em> 内容的 C <code class="xref c c-type docutils literal notranslate"><span class="pre">double</span></code> 表示，但没有错误检查。</p>
|
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</dd></dl>
|
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|
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<dl class="function">
|
||
<dt id="c.PyFloat_GetInfo">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyFloat_GetInfo</code><span class="sig-paren">(</span>void<span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_GetInfo" title="永久链接至目标">¶</a></dt>
|
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<dd><em class="refcount">Return value: New reference.</em><p>返回一个 structseq 实例，其中包含有关 float 的精度、最小值和最大值的信息。 它是头文件 <code class="file docutils literal notranslate"><span class="pre">float.h</span></code> 的一个简单包装。</p>
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</dd></dl>
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|
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<dl class="function">
|
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<dt id="c.PyFloat_GetMax">
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double <code class="sig-name descname">PyFloat_GetMax</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_GetMax" title="永久链接至目标">¶</a></dt>
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<dd><p>返回最大可表示的有限浮点数 <em>DBL_MAX</em> 为 C <code class="xref c c-type docutils literal notranslate"><span class="pre">double</span></code> 。</p>
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</dd></dl>
|
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|
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<dl class="function">
|
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<dt id="c.PyFloat_GetMin">
|
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double <code class="sig-name descname">PyFloat_GetMin</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_GetMin" title="永久链接至目标">¶</a></dt>
|
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<dd><p>返回最小可表示归一化正浮点数 <em>DBL_MIN</em> 为 C <code class="xref c c-type docutils literal notranslate"><span class="pre">double</span></code> 。</p>
|
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</dd></dl>
|
||
|
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<dl class="function">
|
||
<dt id="c.PyFloat_ClearFreeList">
|
||
int <code class="sig-name descname">PyFloat_ClearFreeList</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyFloat_ClearFreeList" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>清空浮点数释放列表。 返回无法释放的项目数。</p>
|
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</dd></dl>
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