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Simplest way to sum two Lists in Scala?

Tags:

scala

I have two lists, I want to sum each element in list A with the element in list B, producing a new list.

I can do it with:

List(1,2).zip(List(5,5)).map(t => t._1 + t._2)

Is there any simpler or neater way to do this in Scala?

In Clojure I can just do:

(map + [1 2 3] [4 5 6])
like image 906
Phil Avatar asked Dec 22 '11 08:12

Phil


2 Answers

For two lists:

(List(1,2), List(5,5)).zipped.map(_ + _)

For three lists:

(List(1,2), List(5,5), List(9, 4)).zipped.map(_ + _ + _)

For n lists:

List(List(1, 2), List(5, 5), List(9, 4), List(6, 3)).transpose.map(_.sum)
like image 147
missingfaktor Avatar answered Oct 20 '22 03:10

missingfaktor


missingfaktor's answer is what I would have recommended, too.

But you could even improve your snippet to get rid of using the clumsy _1, _2:

List(1,2) zip List(5,5) map { case (a, b) => a + b }
like image 30
Heiko Seeberger Avatar answered Oct 20 '22 01:10

Heiko Seeberger