Take this simple RDD as an example for explaining the problem:
val testRDD=sc.parallelize(List((1, 2), (3, 4), (3, 6)))
I have this function to help me implement the indexing:
var sum = 0;
def inc(l: Int): Int = {
sum += l
sum
}
Now I want to create the id for each tuple:
val indexedRDD= testRDD.map(x=>(x._1,x._2,inc(1)));
The output RDD should be ((1,2,1), (3,4,2), (3,6,3))
But it turned out that all the values are same. It is taking 1 for all the tuples:
((1,2,1), (3,4,1), (3,6,1))
Where am I going wrong? Is there any other way to achieve the same.
You are looking for:
def zipWithIndex(): RDD[(T, Long)]
However, note from the docs:
Note that some RDDs, such as those returned by groupBy(), do not guarantee order of elements in a partition. The index assigned to each element is therefore not guaranteed, and may even change if the RDD is reevaluated. If a fixed ordering is required to guarantee the same index assignments, you should sort the RDD with sortByKey() or save it to a file.
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