Global Sort + ZipWithIndex

[Thomas FOURNIER]

Hello,

I'm trying to assign a unique (and deterministic) ID to a globally sorted DataSet.

Given a DataSet of String, I'm computing the frequency of each label as follows:

val env = ExecutionEnvironment.getExecutionEnvironment

val data = env.fromCollection(List("a","b","c","a","a","d","a","a","a","b","b","c","a","c","b","c"))

val mapping = data.map(s => (s,1))
.groupBy(0)
  .reduce((a,b) => (a._1, a._2 + b._2))
  .partitionByRange(1)
  .sortPartition(1, Order.DESCENDING)

Then I want the most frequent label to be ID 0 and so on in a decreasing order. My idea was to use zipWithIndex.

val result = mapping.zipWithIndex

But this does not guarantee that the global order will be preserved right ? What can I do to get such mapping ?

Thanks

Regards

Thomas