Finding sum of elements in Swift array

Question

What is the easiest (best) way to find the sum of an array of integers in swift? I have an array called multiples and I would like to know the sum of the multiples.

Answer 1

Swift 3

If you have an array of generic objects and you want to sum some object property then:

class A: NSObject {
    var value = 0
    init(value: Int) {
       self.value = value
    }
}

let array = [A(value: 2), A(value: 4)]      
let sum = array.reduce(0, { $0 + $1.value })
//                           ^       ^
//                        $0=result  $1=next A object
print(sum) // 6 

Despite of the shorter form, many times you may prefer the classic for-cycle:

let array = [A(value: 2), A(value: 4)]
var sum = 0
array.forEach({ sum += $0.value}) 
// or
for element in array {
   sum += element.value
}