CODEWITHSUNDEEP
scalascala-collections
Laxmikanth Samudrala
Laxmikanth Samudrala

Reputation: 2243

Scala List difference with index information

I have two Lists

val l1 = List(1,2,3)

val l2 = List(1,3,3)

with

l1.diff(l2)

I can find the difference in the list; at the same time I am interested in index where the difference found also; can i know what is the solution in scala ?

Note : All the time both the list size is going to be same.

Upvotes: 1

Views: 464

Answers (3)

thoredge
thoredge

Reputation: 12631

Another way which shows you very easy which list and where you can find the value:

l1.diff(l2).map(v => (v, l1.indexOf(v), l2.indexOf(v)))
// res6: List[(Int, Int, Int)] = List((2,1,-1))

Upvotes: -1

Sascha Kolberg
Sascha Kolberg

Reputation: 7162

You can just add indexes to both lists and diff then:

val diff = l1.zipWithIndex.diff(l2.zipWithIndex)
-> List((2,1)) // different value is 2 and index is 1

Upvotes: 7

ka4eli
ka4eli

Reputation: 5424

val indexes = (l1 zip l2 zipWithIndex).filter(x => x._1._1 != x._1._2).map(_._2)

val indexesWithDiffValues = (l1 zip l2 zipWithIndex).filter(x => x._1._1 != x._1._2)

this code will give you a list of indexes you want.

Upvotes: 2

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