Difference between groupByKey vs reduceByKey in Apache Spark?
Answer / Pradeep Kumar Bhati
groupByKey aggregates data by key and returns an RDD of key-value pairs, while reduceByKey performs a reduction operation on values for each key. The main difference is that groupByKey creates intermediate results as collections (e.g., lists or arrays), whereas reduceByKey uses a custom function to combine values without storing intermediate results.
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