sum and average functions for numeric array

Collection+SumAverage.swift

import Foundation

extension Collection where Element == Int {
    
    func sum() -> Int {
        return reduce(0, +)
    }
    
    func average() -> Double {
        let value = sum()
        return Double(value) / Double(count)
    }
    
}

extension Collection where Element == Float {
    
    func sum() -> Float {
        return reduce(0, +)
    }
    
    func average() -> Float {
        return sum() / Float(count)
    }
    
}

extension Collection where Element == Double {
    
    func sum() -> Double {
        return reduce(0, +)
    }
    
    func average() -> Double {
        return sum() / Double(count)
    }
    
}