Swift running sum

Question

I\'d like a function runningSum on an array of numbers a (or any ordered collection of addable things) that returns an array of the same length where each eleme

Answer 1

Assuming an array of Ints, sounds like you can use map to manipulate the input:

let arr = [0,1,0,1,0,1]

var sum = 0
let val = arr.map { (sum += $0, sum).1 }

print(val) // "[0, 1, 1, 2, 2, 3]\n"

I'll keep working on a solution that doesn't use an external variable.