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| <html> |
| <h2>GroupByKey</h2> |
| <p> |
| GroupByKey is a Beam transform for processing collections of key/value pairs. It’s a parallel |
| reduction operation, analogous to the Shuffle phase of a Map/Shuffle/Reduce-style algorithm. The |
| input to GroupByKey is a collection of key/value pairs that represents a multimap, where the |
| collection contains multiple pairs that have the same key, but different values. Given such a |
| collection, you use GroupByKey to collect all of the values associated with each unique key. |
| </p> |
| <p> |
| <b>Kata:</b> Implement a |
| <a href="https://beam.apache.org/releases/javadoc/current/org/apache/beam/sdk/transforms/GroupByKey.html"> |
| GroupByKey</a> transform that groups words by its first letter. |
| </p> |
| <br> |
| <div class="hint"> |
| Refer to <a href="https://beam.apache.org/releases/javadoc/current/org/apache/beam/sdk/values/KV.html"> |
| KV</a> and |
| <a href="https://beam.apache.org/releases/javadoc/current/org/apache/beam/sdk/transforms/GroupByKey.html"> |
| GroupByKey</a> to solve this problem. |
| </div> |
| <div class="hint"> |
| Refer to the Beam Programming Guide |
| <a href="https://beam.apache.org/documentation/programming-guide/#groupbykey"> |
| "GroupByKey"</a> section for more information. |
| </div> |
| </html> |
