Counting the number of elements in a dataset

[Sebastian Schelter]

Hi,

Is there a simple way to count the number of elements of a dataset? At 
the moment, I have to use the following code, which is pretty verbose 
and unefficient.

    val numVertices =
      (srcVertices union targetVertices).distinct.reduceGroup { iter =>
        var count = 1L
        while (iter.hasNext) {
          count += 1
          iter.next
        }
        count
      }

Best,
Sebastian