How to add elements into map?

[Tim Chou]

Here is the code I run in spark-shell:

val table = sc.textFile(args(1))
val histMap = collection.mutable.Map[Int,Int]()
for (x <- table) {


        val tuple = x.split('|')

          histMap.put(tuple(0).toInt, 1)


    }

Why is histMap still null?
Is there something wrong with my code?

Thanks,
Fang