Sum an Array - Objective-C

Question

I\'m just starting out and I\'m looking for an easy way to sum a simple array. I\'ve read into apple developer site on key value coding and I don\'t understand how to apply

Answer 1

In Swift 4:

let array = [1,2,3,5]
let sum = array.reduce(0, {$0 + $1})
print(sum)

Answer 2

Swift 3: (Dave DeLong's method transformed):

let sum = (numArray as AnyObject).value(forKeyPath:"@sum.self") as! Double

This should work in a similar fashion to it's Objective-C counterpart.

Answer 3

The automatic way to do it is:

NSNumber * sum = [numArray valueForKeyPath:@"@sum.self"];

But if you're just starting out, I would recommend avoiding the collection key-path operators and go for the more simple way:

double sum = 0;
for (NSNumber * n in numArray) {
  sum += [n doubleValue];
}