Scala Functional style of converting Array[Int] to Map[Int, Int]

Question

I want to convert an Array[Int] to a Map[Int, Int] where each key is the element of the array and the respective value is the index of the element in the array.

Array(11, 12, 13) => Map((11,0), (12,1), (13,2))

Is it possible to do this without using a Mutable map, with a more functional style?

for example:

myArray.toMap(implicit def (... ))

This means, of course, that there will be data loss if your Array has any duplicate values: Array(2,3,2) — jwvh
– jwvh, Commented Oct 22, 2019 at 7:31

Andriy Plokhotnyuk · Accepted Answer · 2019-10-22 11:49:52Z

6

scala> Array(11, 12, 13).zipWithIndex.toMap
res0: scala.collection.immutable.Map[Int,Int] = Map(11 -> 0, 12 -> 1, 13 -> 2)

P.S. But use HashMap/HashSet from Scala collections wisely to avoid security vulnerabilities on untrusted input under DoS/DoW attacks that exploit hash collision vulnerabilities of them directly or indirectly through Scala collections methods that use them under hood: toMap, keys, distinct, groupBy, etc..

edited Oct 22, 2019 at 11:49

answered Oct 22, 2019 at 7:07

Andriy Plokhotnyuk

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