SubtractByKey
Very similar to subtract, but instead of supplying a function, the key-component of each pair will be automatically used as criterion for removing items from the first RDD.
Listing Variants:
def subtractByKey[W: ClassTag](other: RDD[(K, W)]): RDD[(K, V)]
def subtractByKey[W: ClassTag](other: RDD[(K, W)], numPartitions: Int): RDD[(K, V)]
def subtractByKey[W: ClassTag](other: RDD[(K, W)], p: Partitioner): RDD[(K, V)]