How to sum a list of tuples

Question

Given the following list of tuples...

val list = List((1, 2), (1, 2), (1, 2))

... how do I sum all the values and obtain a single tuple lik

Answer 1

You can solve this using Monoid.combineAll from the cats library:

import cats.instances.int._ // For monoid instances for `Int`
import cats.instances.tuple._  // for Monoid instance for `Tuple2`
import cats.Monoid.combineAll

  def main(args: Array[String]): Unit = {

    val list = List((1, 2), (1, 2), (1, 2))

    val res = combineAll(list)

    println(res)
    // Displays
    // (3, 6)
  }

You can see more about this in the cats documentation or Scala with Cats.