比較Double Swift 4的兩個數組

Question

有兩個Doubles數組，我想將它們進行比較並創建一個具有差異結果的新數組，但不確定如何為此創建循環。 請指教。

數組示例：

 var freshRates = [1.6,1.7,2.0]
 var oldRates = [1.5,1.4,1.9]
 var difference: [Double] = []

Answer 1

壓縮數組以獲得元組數組，然后僅使用map計算每對的差：

var freshRates = [1.6,1.7,2.0]
var oldRates = [1.5,1.4,1.9]
var difference: [Double] = zip(freshRates, oldRates).map({ $0.0 - $0.1 })

Answer 2

var freshRates = [1.6,1.7,2.0]
var oldRates = [1.5,1.4,1.9]
var difference: [Double] = []

for (val1,val2) in zip(freshRates, oldRates){
    difference.append(val2 - val1)
}

debugPrint(difference)