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| <div class="section" id="module-apache_beam.pvalue"> |
| <span id="apache-beam-pvalue-module"></span><h1>apache_beam.pvalue module<a class="headerlink" href="#module-apache_beam.pvalue" title="Permalink to this headline">¶</a></h1> |
| <p>PValue, PCollection: one node of a dataflow graph.</p> |
| <p>A node of a dataflow processing graph is a PValue. Currently, there is only |
| one type: PCollection (a potentially very large set of arbitrary values). |
| Once created, a PValue belongs to a pipeline and has an associated |
| transform (of type PTransform), which describes how the value will be |
| produced when the pipeline gets executed.</p> |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.PCollection"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">PCollection</code><span class="sig-paren">(</span><em>pipeline</em>, <em>tag=None</em>, <em>element_type=None</em>, <em>windowing=None</em>, <em>is_bounded=True</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#PCollection"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.PCollection" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <code class="xref py py-class docutils literal notranslate"><span class="pre">apache_beam.pvalue.PValue</span></code>, <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Generic" title="(in Python v3.9)"><code class="xref py py-class docutils literal notranslate"><span class="pre">typing.Generic</span></code></a></p> |
| <p>A multiple values (potentially huge) container.</p> |
| <p>Dataflow users should not construct PCollection objects directly in their |
| pipelines.</p> |
| <p>Initializes a PValue with all arguments hidden behind keyword arguments.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name" /> |
| <col class="field-body" /> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple"> |
| <li><strong>pipeline</strong> – Pipeline object for this PValue.</li> |
| <li><strong>tag</strong> – Tag of this PValue.</li> |
| <li><strong>element_type</strong> – The type of this PValue.</li> |
| </ul> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| <dl class="attribute"> |
| <dt id="apache_beam.pvalue.PCollection.windowing"> |
| <code class="descname">windowing</code><a class="headerlink" href="#apache_beam.pvalue.PCollection.windowing" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
| <dl class="staticmethod"> |
| <dt id="apache_beam.pvalue.PCollection.from_"> |
| <em class="property">static </em><code class="descname">from_</code><span class="sig-paren">(</span><em>pcoll</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#PCollection.from_"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.PCollection.from_" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Create a PCollection, using another PCollection as a starting point.</p> |
| <p>Transfers relevant attributes.</p> |
| </dd></dl> |
| |
| <dl class="method"> |
| <dt id="apache_beam.pvalue.PCollection.to_runner_api"> |
| <code class="descname">to_runner_api</code><span class="sig-paren">(</span><em>context</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#PCollection.to_runner_api"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.PCollection.to_runner_api" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
| <dl class="staticmethod"> |
| <dt id="apache_beam.pvalue.PCollection.from_runner_api"> |
| <em class="property">static </em><code class="descname">from_runner_api</code><span class="sig-paren">(</span><em>proto</em>, <em>context</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#PCollection.from_runner_api"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.PCollection.from_runner_api" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.TaggedOutput"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">TaggedOutput</code><span class="sig-paren">(</span><em>tag</em>, <em>value</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#TaggedOutput"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.TaggedOutput" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <a class="reference external" href="https://docs.python.org/3/library/functions.html#object" title="(in Python v3.9)"><code class="xref py py-class docutils literal notranslate"><span class="pre">object</span></code></a></p> |
| <p>An object representing a tagged value.</p> |
| <p>ParDo, Map, and FlatMap transforms can emit values on multiple outputs which |
| are distinguished by string tags. The DoFn will return plain values |
| if it wants to emit on the main output and TaggedOutput objects |
| if it wants to emit a value on a specific tagged output.</p> |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.AsSingleton"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">AsSingleton</code><span class="sig-paren">(</span><em>pcoll</em>, <em>default_value=<object object></em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#AsSingleton"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.AsSingleton" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <code class="xref py py-class docutils literal notranslate"><span class="pre">apache_beam.pvalue.AsSideInput</span></code></p> |
| <p>Marker specifying that an entire PCollection is to be used as a side input.</p> |
| <p>When a PCollection is supplied as a side input to a PTransform, it is |
| necessary to indicate whether the entire PCollection should be made available |
| as a PTransform side argument (in the form of an iterable), or whether just |
| one value should be pulled from the PCollection and supplied as the side |
| argument (as an ordinary value).</p> |
| <p>Wrapping a PCollection side input argument to a PTransform in this container |
| (e.g., data.apply(‘label’, MyPTransform(), AsSingleton(my_side_input) ) |
| selects the latter behavior.</p> |
| <p>The input PCollection must contain exactly one value per window, unless a |
| default is given, in which case it may be empty.</p> |
| <dl class="attribute"> |
| <dt id="apache_beam.pvalue.AsSingleton.element_type"> |
| <code class="descname">element_type</code><a class="headerlink" href="#apache_beam.pvalue.AsSingleton.element_type" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.AsIter"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">AsIter</code><span class="sig-paren">(</span><em>pcoll</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#AsIter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.AsIter" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <code class="xref py py-class docutils literal notranslate"><span class="pre">apache_beam.pvalue.AsSideInput</span></code></p> |
| <p>Marker specifying that an entire PCollection is to be used as a side input.</p> |
| <p>When a PCollection is supplied as a side input to a PTransform, it is |
| necessary to indicate whether the entire PCollection should be made available |
| as a PTransform side argument (in the form of an iterable), or whether just |
| one value should be pulled from the PCollection and supplied as the side |
| argument (as an ordinary value).</p> |
| <p>Wrapping a PCollection side input argument to a PTransform in this container |
| (e.g., data.apply(‘label’, MyPTransform(), AsIter(my_side_input) ) selects the |
| former behavor.</p> |
| <dl class="attribute"> |
| <dt id="apache_beam.pvalue.AsIter.element_type"> |
| <code class="descname">element_type</code><a class="headerlink" href="#apache_beam.pvalue.AsIter.element_type" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.AsList"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">AsList</code><span class="sig-paren">(</span><em>pcoll</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#AsList"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.AsList" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <code class="xref py py-class docutils literal notranslate"><span class="pre">apache_beam.pvalue.AsSideInput</span></code></p> |
| <p>Marker specifying that an entire PCollection is to be used as a side input.</p> |
| <p>Intended for use in side-argument specification—the same places where |
| AsSingleton and AsIter are used, but forces materialization of this |
| PCollection as a list.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name" /> |
| <col class="field-body" /> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>pcoll</strong> – Input pcollection.</td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">An AsList-wrapper around a PCollection whose one element is a list |
| containing all elements in pcoll.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.AsDict"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">AsDict</code><span class="sig-paren">(</span><em>pcoll</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#AsDict"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.AsDict" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <code class="xref py py-class docutils literal notranslate"><span class="pre">apache_beam.pvalue.AsSideInput</span></code></p> |
| <p>Marker specifying a PCollection to be used as an indexable side input.</p> |
| <p>Intended for use in side-argument specification—the same places where |
| AsSingleton and AsIter are used, but returns an interface that allows |
| key lookup.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name" /> |
| <col class="field-body" /> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>pcoll</strong> – Input pcollection. All elements should be key-value pairs (i.e. |
| 2-tuples) with unique keys.</td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><dl class="docutils"> |
| <dt>An AsDict-wrapper around a PCollection whose one element is a dict with</dt> |
| <dd>entries for uniquely-keyed pairs in pcoll.</dd> |
| </dl> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.EmptySideInput"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">EmptySideInput</code><a class="reference internal" href="_modules/apache_beam/pvalue.html#EmptySideInput"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.EmptySideInput" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <a class="reference external" href="https://docs.python.org/3/library/functions.html#object" title="(in Python v3.9)"><code class="xref py py-class docutils literal notranslate"><span class="pre">object</span></code></a></p> |
| <p>Value indicating when a singleton side input was empty.</p> |
| <p>If a PCollection was furnished as a singleton side input to a PTransform, and |
| that PCollection was empty, then this value is supplied to the DoFn in the |
| place where a value from a non-empty PCollection would have gone. This alerts |
| the DoFn that the side input PCollection was empty. Users may want to check |
| whether side input values are EmptySideInput, but they will very likely never |
| want to create new instances of this class themselves.</p> |
| </dd></dl> |
| |
| <dl class="class"> |
| <dt id="apache_beam.pvalue.Row"> |
| <em class="property">class </em><code class="descclassname">apache_beam.pvalue.</code><code class="descname">Row</code><span class="sig-paren">(</span><em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#Row"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.Row" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Bases: <a class="reference external" href="https://docs.python.org/3/library/functions.html#object" title="(in Python v3.9)"><code class="xref py py-class docutils literal notranslate"><span class="pre">object</span></code></a></p> |
| <p>A dynamic schema’d row object.</p> |
| <p>This objects attributes are initialized from the keywords passed into its |
| constructor, e.g. Row(x=3, y=4) will create a Row with two attributes x and y.</p> |
| <p>More importantly, when a Row object is returned from a <cite>Map</cite>, <cite>FlatMap</cite>, or |
| <cite>DoFn</cite> type inference is able to deduce the schema of the resulting |
| PCollection, e.g.</p> |
| <blockquote> |
| <div>pc | beam.Map(lambda x: Row(x=x, y=0.5 * x))</div></blockquote> |
| <p>when applied to a PCollection of ints will produce a PCollection with schema |
| <cite>(x=int, y=float)</cite>.</p> |
| <p>Note that in Beam 2.30.0 and later, Row objects are sensitive to field order. |
| So <cite>Row(x=3, y=4)</cite> is not considered equal to <cite>Row(y=4, x=3)</cite>.</p> |
| <dl class="method"> |
| <dt id="apache_beam.pvalue.Row.as_dict"> |
| <code class="descname">as_dict</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/pvalue.html#Row.as_dict"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.pvalue.Row.as_dict" title="Permalink to this definition">¶</a></dt> |
| <dd></dd></dl> |
| |
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