learning/katas/python/Core Transforms/Combine/Combine PerKey/task.html - beam - Git at Google

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 <html>
 <h2>Combine - Combine PerKey</h2>
 <p>
   After creating a keyed PCollection (for example, by using a GroupByKey transform), a common
   pattern is to combine the collection of values associated with each key into a single, merged
   value. This pattern of a GroupByKey followed by merging the collection of values is equivalent to
   Combine PerKey transform. The combine function you supply to Combine PerKey must be an associative
   reduction function or a subclass of CombineFn.
 </p>
 <p>
   <b>Kata:</b> Implement the sum of scores per player using
   <a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombinePerKey">
     CombinePerKey</a>.
 </p>
 <br>
 <div class="hint">
   Use <a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombinePerKey">
   CombinePerKey(CombineFn)</a>.
 </div>
 <div class="hint">
   Extend the
   <a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombineFn">
     CombineFn</a> class that counts the sum of the number.
 </div>
 <div class="hint">
   Refer to the Beam Programming Guide
   <a href="https://beam.apache.org/documentation/programming-guide/#combining-values-in-a-keyed-pcollection">
     "Combining values in a keyed PCollection"</a> section for more information.
 </div>
 </html>
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	<html>
	<h2>Combine - Combine PerKey</h2>
	<p>
	After creating a keyed PCollection (for example, by using a GroupByKey transform), a common
	pattern is to combine the collection of values associated with each key into a single, merged
	value. This pattern of a GroupByKey followed by merging the collection of values is equivalent to
	Combine PerKey transform. The combine function you supply to Combine PerKey must be an associative
	reduction function or a subclass of CombineFn.
	</p>
	<p>
	<b>Kata:</b> Implement the sum of scores per player using
	<a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombinePerKey">
	CombinePerKey</a>.
	</p>
	<br>
	<div class="hint">
	Use <a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombinePerKey">
	CombinePerKey(CombineFn)</a>.
	</div>
	<div class="hint">
	Extend the
	<a href="https://beam.apache.org/releases/pydoc/current/apache_beam.transforms.core.html#apache_beam.transforms.core.CombineFn">
	CombineFn</a> class that counts the sum of the number.
	</div>
	<div class="hint">
	Refer to the Beam Programming Guide
	<a href="https://beam.apache.org/documentation/programming-guide/#combining-values-in-a-keyed-pcollection">
	"Combining values in a keyed PCollection"</a> section for more information.
	</div>
	</html>