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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code> --- 一个同步的队列类</a><ul>
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<section id="module-queue">
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<span id="queue-a-synchronized-queue-class"></span><h1><a class="reference internal" href="#module-queue" title="queue: A synchronized queue class."><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code></a> --- 一个同步的队列类<a class="headerlink" href="#module-queue" title="永久链接至标题">¶</a></h1>
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<p><strong>源代码:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.8/Lib/queue.py">Lib/queue.py</a></p>
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<hr class="docutils" />
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<p><a class="reference internal" href="#module-queue" title="queue: A synchronized queue class."><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code></a> 模块实现了多生产者、多消费者队列。这特别适用于消息必须安全地在多线程间交换的线程编程。模块中的 <a class="reference internal" href="#queue.Queue" title="queue.Queue"><code class="xref py py-class docutils literal notranslate"><span class="pre">Queue</span></code></a> 类实现了所有所需的锁定语义。</p>
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<p>模块实现了三种类型的队列，它们的区别仅仅是条目取回的顺序。在 <abbr title="first-in, first-out">FIFO</abbr> 队列中，先添加的任务先取回。在 <abbr title="last-in, first-out">LIFO</abbr> 队列中，最近被添加的条目先取回(操作类似一个堆栈)。优先级队列中，条目将保持排序( 使用 <a class="reference internal" href="heapq.html#module-heapq" title="heapq: Heap queue algorithm (a.k.a. priority queue)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">heapq</span></code></a> 模块 ) 并且最小值的条目第一个返回。</p>
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<p>在内部，这三个类型的队列使用锁来临时阻塞竞争线程；然而，它们并未被设计用于线程的重入性处理。</p>
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<p>此外，模块实现了一个 "简单的" <abbr title="first-in, first-out">FIFO</abbr> 队列类型， <a class="reference internal" href="#queue.SimpleQueue" title="queue.SimpleQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">SimpleQueue</span></code></a> ，这个特殊实现为小功能在交换中提供额外的保障。</p>
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<p><a class="reference internal" href="#module-queue" title="queue: A synchronized queue class."><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code></a> 模块定义了下列类和异常：</p>
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<dl class="class">
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<dt id="queue.Queue">
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<em class="property">class </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">Queue</code><span class="sig-paren">(</span><em class="sig-param">maxsize=0</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue" title="永久链接至目标">¶</a></dt>
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<dd><p>Constructor for a <abbr title="first-in, first-out">FIFO</abbr> queue. <em>maxsize</em> is
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an integer that sets the upperbound
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limit on the number of items that can be placed in the queue. Insertion will
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block once this size has been reached, until queue items are consumed. If
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<em>maxsize</em> is less than or equal to zero, the queue size is infinite.</p>
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</dd></dl>
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<dl class="class">
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<dt id="queue.LifoQueue">
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<em class="property">class </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">LifoQueue</code><span class="sig-paren">(</span><em class="sig-param">maxsize=0</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.LifoQueue" title="永久链接至目标">¶</a></dt>
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<dd><p><abbr title="last-in, first-out">LIFO</abbr> 队列构造函数。 <em>maxsize</em> 是个整数，用于设置可以放入队列中的项目数的上限。当达到这个大小的时候，插入操作将阻塞至队列中的项目被消费掉。如果 <em>maxsize</em> 小于等于零，队列尺寸为无限大。</p>
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</dd></dl>
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<dl class="class">
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<dt id="queue.PriorityQueue">
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<em class="property">class </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">PriorityQueue</code><span class="sig-paren">(</span><em class="sig-param">maxsize=0</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.PriorityQueue" title="永久链接至目标">¶</a></dt>
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<dd><p>优先级队列构造函数。 <em>maxsize</em> 是个整数，用于设置可以放入队列中的项目数的上限。当达到这个大小的时候，插入操作将阻塞至队列中的项目被消费掉。如果 <em>maxsize</em> 小于等于零，队列尺寸为无限大。</p>
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<p>最小值先被取出( 最小值条目是由 <code class="docutils literal notranslate"><span class="pre">sorted(list(entries))[0]</span></code> 返回的条目)。条目的典型模式是一个以下形式的元组： <code class="docutils literal notranslate"><span class="pre">(priority_number,</span> <span class="pre">data)</span></code> 。</p>
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<p>如果 <em>data</em> 元素没有可比性，数据将被包装在一个类中，忽略数据值，仅仅比较优先级数字 ：</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">dataclasses</span> <span class="kn">import</span> <span class="n">dataclass</span><span class="p">,</span> <span class="n">field</span>
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<span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Any</span>
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<span class="nd">@dataclass</span><span class="p">(</span><span class="n">order</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
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<span class="k">class</span> <span class="nc">PrioritizedItem</span><span class="p">:</span>
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<span class="n">priority</span><span class="p">:</span> <span class="nb">int</span>
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<span class="n">item</span><span class="p">:</span> <span class="n">Any</span><span class="o">=</span><span class="n">field</span><span class="p">(</span><span class="n">compare</span><span class="o">=</span><span class="kc">False</span><span class="p">)</span>
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</pre></div>
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</div>
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</dd></dl>
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<dl class="class">
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<dt id="queue.SimpleQueue">
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<em class="property">class </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">SimpleQueue</code><a class="headerlink" href="#queue.SimpleQueue" title="永久链接至目标">¶</a></dt>
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<dd><p>无界的 <abbr title="first-in, first-out">FIFO</abbr> 队列构造函数。简单的队列，缺少任务跟踪等高级功能。</p>
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<div class="versionadded">
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<p><span class="versionmodified added">3.7 新版功能.</span></p>
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</div>
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</dd></dl>
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<dl class="exception">
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<dt id="queue.Empty">
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<em class="property">exception </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">Empty</code><a class="headerlink" href="#queue.Empty" title="永久链接至目标">¶</a></dt>
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<dd><p>对空的 <a class="reference internal" href="#queue.Queue" title="queue.Queue"><code class="xref py py-class docutils literal notranslate"><span class="pre">Queue</span></code></a> 对象，调用非阻塞的 <a class="reference internal" href="#queue.Queue.get" title="queue.Queue.get"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get()</span></code></a> (or <a class="reference internal" href="#queue.Queue.get_nowait" title="queue.Queue.get_nowait"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_nowait()</span></code></a>) 时，引发的异常。</p>
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</dd></dl>
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<dl class="exception">
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<dt id="queue.Full">
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<em class="property">exception </em><code class="sig-prename descclassname">queue.</code><code class="sig-name descname">Full</code><a class="headerlink" href="#queue.Full" title="永久链接至目标">¶</a></dt>
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<dd><p>对满的 <a class="reference internal" href="#queue.Queue" title="queue.Queue"><code class="xref py py-class docutils literal notranslate"><span class="pre">Queue</span></code></a> 对象，调用非阻塞的 <a class="reference internal" href="#queue.Queue.put" title="queue.Queue.put"><code class="xref py py-meth docutils literal notranslate"><span class="pre">put()</span></code></a> (or <a class="reference internal" href="#queue.Queue.put_nowait" title="queue.Queue.put_nowait"><code class="xref py py-meth docutils literal notranslate"><span class="pre">put_nowait()</span></code></a>) 时，引发的异常。</p>
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</dd></dl>
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<section id="queue-objects">
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<span id="queueobjects"></span><h2>Queue对象<a class="headerlink" href="#queue-objects" title="永久链接至标题">¶</a></h2>
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<p>队列对象 (<a class="reference internal" href="#queue.Queue" title="queue.Queue"><code class="xref py py-class docutils literal notranslate"><span class="pre">Queue</span></code></a>, <a class="reference internal" href="#queue.LifoQueue" title="queue.LifoQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">LifoQueue</span></code></a>, 或者 <a class="reference internal" href="#queue.PriorityQueue" title="queue.PriorityQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">PriorityQueue</span></code></a>) 提供下列描述的公共方法。</p>
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<dl class="method">
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<dt id="queue.Queue.qsize">
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<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">qsize</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.qsize" title="永久链接至目标">¶</a></dt>
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<dd><p>返回队列的大致大小。注意，qsize() > 0 不保证后续的 get() 不被阻塞，qsize() < maxsize 也不保证 put() 不被阻塞。</p>
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</dd></dl>
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<dl class="method">
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<dt id="queue.Queue.empty">
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<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">empty</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.empty" title="永久链接至目标">¶</a></dt>
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<dd><p>如果队列为空，返回 <code class="docutils literal notranslate"><span class="pre">True</span></code> ，否则返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> 。如果 empty() 返回 <code class="docutils literal notranslate"><span class="pre">True</span></code> ，不保证后续调用的 put() 不被阻塞。类似的，如果 empty() 返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> ，也不保证后续调用的 get() 不被阻塞。</p>
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</dd></dl>
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<dl class="method">
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<dt id="queue.Queue.full">
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<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">full</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.full" title="永久链接至目标">¶</a></dt>
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<dd><p>如果队列是满的返回 <code class="docutils literal notranslate"><span class="pre">True</span></code> ，否则返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> 。如果 full() 返回 <code class="docutils literal notranslate"><span class="pre">True</span></code> 不保证后续调用的 get() 不被阻塞。类似的，如果 full() 返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> 也不保证后续调用的 put() 不被阻塞。</p>
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</dd></dl>
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<dl class="method">
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<dt id="queue.Queue.put">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">put</code><span class="sig-paren">(</span><em class="sig-param">item</em>, <em class="sig-param">block=True</em>, <em class="sig-param">timeout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.put" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>将 <em>item</em> 放入队列。如果可选参数 <em>block</em> 是 true 并且 <em>timeout</em> 是 <code class="docutils literal notranslate"><span class="pre">None</span></code> (默认)，则在必要时阻塞至有空闲插槽可用。如果 <em>timeout</em> 是个正数，将最多阻塞 <em>timeout</em> 秒，如果在这段时间没有可用的空闲插槽，将引发 <a class="reference internal" href="#queue.Full" title="queue.Full"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Full</span></code></a> 异常。反之 (<em>block</em> 是 false)，如果空闲插槽立即可用，则把 <em>item</em> 放入队列，否则引发 <a class="reference internal" href="#queue.Full" title="queue.Full"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Full</span></code></a> 异常 ( 在这种情况下，<em>timeout</em> 将被忽略)。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.Queue.put_nowait">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">put_nowait</code><span class="sig-paren">(</span><em class="sig-param">item</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.put_nowait" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>相当于 <code class="docutils literal notranslate"><span class="pre">put(item,</span> <span class="pre">False)</span></code> 。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.Queue.get">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">get</code><span class="sig-paren">(</span><em class="sig-param">block=True</em>, <em class="sig-param">timeout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.get" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>从队列中移除并返回一个项目。如果可选参数 <em>block</em> 是 true 并且 <em>timeout</em> 是 <code class="docutils literal notranslate"><span class="pre">None</span></code> (默认值)，则在必要时阻塞至项目可得到。如果 <em>timeout</em> 是个正数，将最多阻塞 <em>timeout</em> 秒，如果在这段时间内项目不能得到，将引发 <a class="reference internal" href="#queue.Empty" title="queue.Empty"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Empty</span></code></a> 异常。反之 (<em>block</em> 是 false) , 如果一个项目立即可得到，则返回一个项目，否则引发 <a class="reference internal" href="#queue.Empty" title="queue.Empty"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Empty</span></code></a> 异常 (这种情况下，<em>timeout</em> 将被忽略)。</p>
|
||
<p>POSIX系统3.0之前，以及所有版本的Windows系统中，如果 <em>block</em> 是 true 并且 <em>timeout</em> 是 <code class="docutils literal notranslate"><span class="pre">None</span></code> ， 这个操作将进入基础锁的不间断等待。这意味着，没有异常能发生，尤其是 SIGINT 将不会触发 <a class="reference internal" href="exceptions.html#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyboardInterrupt</span></code></a> 异常。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.Queue.get_nowait">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">get_nowait</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.get_nowait" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>相当于 <code class="docutils literal notranslate"><span class="pre">get(False)</span></code> 。</p>
|
||
</dd></dl>
|
||
|
||
<p>提供了两个方法，用于支持跟踪 排队的任务 是否 被守护的消费者线程 完整的处理。</p>
|
||
<dl class="method">
|
||
<dt id="queue.Queue.task_done">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">task_done</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.task_done" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>表示前面排队的任务已经被完成。被队列的消费者线程使用。每个 <a class="reference internal" href="#queue.Queue.get" title="queue.Queue.get"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get()</span></code></a> 被用于获取一个任务， 后续调用 <a class="reference internal" href="#queue.Queue.task_done" title="queue.Queue.task_done"><code class="xref py py-meth docutils literal notranslate"><span class="pre">task_done()</span></code></a> 告诉队列，该任务的处理已经完成。</p>
|
||
<p>如果 <a class="reference internal" href="#queue.Queue.join" title="queue.Queue.join"><code class="xref py py-meth docutils literal notranslate"><span class="pre">join()</span></code></a> 当前正在阻塞，在所有条目都被处理后，将解除阻塞(意味着每个 <a class="reference internal" href="#queue.Queue.put" title="queue.Queue.put"><code class="xref py py-meth docutils literal notranslate"><span class="pre">put()</span></code></a> 进队列的条目的 <a class="reference internal" href="#queue.Queue.task_done" title="queue.Queue.task_done"><code class="xref py py-meth docutils literal notranslate"><span class="pre">task_done()</span></code></a> 都被收到)。</p>
|
||
<p>如果被调用的次数多于放入队列中的项目数量，将引发 <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> 异常 。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.Queue.join">
|
||
<code class="sig-prename descclassname">Queue.</code><code class="sig-name descname">join</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.Queue.join" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>阻塞至队列中所有的元素都被接收和处理完毕。</p>
|
||
<p>当条目添加到队列的时候，未完成任务的计数就会增加。每当消费者线程调用 <a class="reference internal" href="#queue.Queue.task_done" title="queue.Queue.task_done"><code class="xref py py-meth docutils literal notranslate"><span class="pre">task_done()</span></code></a> 表示这个条目已经被回收，该条目所有工作已经完成，未完成计数就会减少。当未完成计数降到零的时候， <a class="reference internal" href="#queue.Queue.join" title="queue.Queue.join"><code class="xref py py-meth docutils literal notranslate"><span class="pre">join()</span></code></a> 阻塞被解除。</p>
|
||
</dd></dl>
|
||
|
||
<p>如何等待排队的任务被完成的示例：</p>
|
||
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">threading</span><span class="o">,</span> <span class="nn">queue</span>
|
||
|
||
<span class="n">q</span> <span class="o">=</span> <span class="n">queue</span><span class="o">.</span><span class="n">Queue</span><span class="p">()</span>
|
||
|
||
<span class="k">def</span> <span class="nf">worker</span><span class="p">():</span>
|
||
<span class="k">while</span> <span class="kc">True</span><span class="p">:</span>
|
||
<span class="n">item</span> <span class="o">=</span> <span class="n">q</span><span class="o">.</span><span class="n">get</span><span class="p">()</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">'Working on </span><span class="si">{</span><span class="n">item</span><span class="si">}</span><span class="s1">'</span><span class="p">)</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">'Finished </span><span class="si">{</span><span class="n">item</span><span class="si">}</span><span class="s1">'</span><span class="p">)</span>
|
||
<span class="n">q</span><span class="o">.</span><span class="n">task_done</span><span class="p">()</span>
|
||
|
||
<span class="c1"># turn-on the worker thread</span>
|
||
<span class="n">threading</span><span class="o">.</span><span class="n">Thread</span><span class="p">(</span><span class="n">target</span><span class="o">=</span><span class="n">worker</span><span class="p">,</span> <span class="n">daemon</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
|
||
|
||
<span class="c1"># send thirty task requests to the worker</span>
|
||
<span class="k">for</span> <span class="n">item</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">30</span><span class="p">):</span>
|
||
<span class="n">q</span><span class="o">.</span><span class="n">put</span><span class="p">(</span><span class="n">item</span><span class="p">)</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="s1">'All task requests sent</span><span class="se">\n</span><span class="s1">'</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="s1">''</span><span class="p">)</span>
|
||
|
||
<span class="c1"># block until all tasks are done</span>
|
||
<span class="n">q</span><span class="o">.</span><span class="n">join</span><span class="p">()</span>
|
||
<span class="nb">print</span><span class="p">(</span><span class="s1">'All work completed'</span><span class="p">)</span>
|
||
</pre></div>
|
||
</div>
|
||
</section>
|
||
<section id="simplequeue-objects">
|
||
<h2>SimpleQueue 对象<a class="headerlink" href="#simplequeue-objects" title="永久链接至标题">¶</a></h2>
|
||
<p><a class="reference internal" href="#queue.SimpleQueue" title="queue.SimpleQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">SimpleQueue</span></code></a> 对象提供下列描述的公共方法。</p>
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.qsize">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">qsize</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.qsize" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>返回队列的大致大小。注意，qsize() > 0 不保证后续的 get() 不被阻塞。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.empty">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">empty</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.empty" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>如果队列为空，返回 <code class="docutils literal notranslate"><span class="pre">True</span></code> ，否则返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> 。如果 empty() 返回 <code class="docutils literal notranslate"><span class="pre">False</span></code> ，不保证后续调用的 get() 不被阻塞。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.put">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">put</code><span class="sig-paren">(</span><em class="sig-param">item</em>, <em class="sig-param">block=True</em>, <em class="sig-param">timeout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.put" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>将 <em>item</em> 放入队列。此方法永不阻塞，始终成功（除了潜在的低级错误，例如内存分配失败）。可选参数 <em>block</em> 和 <em>timeout</em> 仅仅是为了保持 <a class="reference internal" href="#queue.Queue.put" title="queue.Queue.put"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Queue.put()</span></code></a> 的兼容性而提供，其值被忽略。</p>
|
||
<div class="impl-detail compound">
|
||
<p><strong>CPython implementation detail:</strong> This method has a C implementation which is reentrant. That is, a
|
||
<code class="docutils literal notranslate"><span class="pre">put()</span></code> or <code class="docutils literal notranslate"><span class="pre">get()</span></code> call can be interrupted by another <code class="docutils literal notranslate"><span class="pre">put()</span></code>
|
||
call in the same thread without deadlocking or corrupting internal
|
||
state inside the queue. This makes it appropriate for use in
|
||
destructors such as <code class="docutils literal notranslate"><span class="pre">__del__</span></code> methods or <a class="reference internal" href="weakref.html#module-weakref" title="weakref: Support for weak references and weak dictionaries."><code class="xref py py-mod docutils literal notranslate"><span class="pre">weakref</span></code></a> callbacks.</p>
|
||
</div>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.put_nowait">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">put_nowait</code><span class="sig-paren">(</span><em class="sig-param">item</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.put_nowait" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>相当于 <code class="docutils literal notranslate"><span class="pre">put(item)</span></code> ，仅为保持 <a class="reference internal" href="#queue.Queue.put_nowait" title="queue.Queue.put_nowait"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Queue.put_nowait()</span></code></a> 兼容性而提供。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.get">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">get</code><span class="sig-paren">(</span><em class="sig-param">block=True</em>, <em class="sig-param">timeout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.get" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>从队列中移除并返回一个项目。如果可选参数 <em>block</em> 是 true 并且 <em>timeout</em> 是 <code class="docutils literal notranslate"><span class="pre">None</span></code> (默认值)，则在必要时阻塞至项目可得到。如果 <em>timeout</em> 是个正数，将最多阻塞 <em>timeout</em> 秒，如果在这段时间内项目不能得到，将引发 <a class="reference internal" href="#queue.Empty" title="queue.Empty"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Empty</span></code></a> 异常。反之 (<em>block</em> 是 false) , 如果一个项目立即可得到，则返回一个项目，否则引发 <a class="reference internal" href="#queue.Empty" title="queue.Empty"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Empty</span></code></a> 异常 (这种情况下，<em>timeout</em> 将被忽略)。</p>
|
||
</dd></dl>
|
||
|
||
<dl class="method">
|
||
<dt id="queue.SimpleQueue.get_nowait">
|
||
<code class="sig-prename descclassname">SimpleQueue.</code><code class="sig-name descname">get_nowait</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#queue.SimpleQueue.get_nowait" title="永久链接至目标">¶</a></dt>
|
||
<dd><p>相当于 <code class="docutils literal notranslate"><span class="pre">get(False)</span></code> 。</p>
|
||
</dd></dl>
|
||
|
||
<div class="admonition seealso">
|
||
<p class="admonition-title">参见</p>
|
||
<dl class="simple">
|
||
<dt>类 <a class="reference internal" href="multiprocessing.html#multiprocessing.Queue" title="multiprocessing.Queue"><code class="xref py py-class docutils literal notranslate"><span class="pre">multiprocessing.Queue</span></code></a></dt><dd><p>一个用于多进程上下文的队列类（而不是多线程）。</p>
|
||
</dd>
|
||
</dl>
|
||
<p><a class="reference internal" href="collections.html#collections.deque" title="collections.deque"><code class="xref py py-class docutils literal notranslate"><span class="pre">collections.deque</span></code></a> 是无界队列的一个替代实现，具有快速的不需要锁并且支持索引的原子化 <a class="reference internal" href="collections.html#collections.deque.append" title="collections.deque.append"><code class="xref py py-meth docutils literal notranslate"><span class="pre">append()</span></code></a> 和 <a class="reference internal" href="collections.html#collections.deque.popleft" title="collections.deque.popleft"><code class="xref py py-meth docutils literal notranslate"><span class="pre">popleft()</span></code></a> 操作。</p>
|
||
</div>
|
||
</section>
|
||
</section>
|
||
|
||
|
||
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|
||
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|
||
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|
||
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|
||
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|
||
<h3><a href="../contents.html">目录</a></h3>
|
||
<ul>
|
||
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code> --- 一个同步的队列类</a><ul>
|
||
<li><a class="reference internal" href="#queue-objects">Queue对象</a></li>
|
||
<li><a class="reference internal" href="#simplequeue-objects">SimpleQueue 对象</a></li>
|
||
</ul>
|
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|
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最后更新于 12月 09, 2024.
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