A common situation in which you’ll find yourself in Spark will be having an RDD of keys and values in two-tuples. A common operation on those keys and values will be summing all the values by key....

A common situation in which you’ll find yourself in Spark will be having an RDD of keys and values in two-tuples. A common operation on those keys and values will be summing all the values by key. This operation can be called sumByKey. Use the right reduce-like method of the RDD to sum the values in an RDD by key.