为什么我会因为索引超出范围而出现致命错误？

Question

var numbers = [45, 73, 195, 53]

//Write your code here
 //Replace this comment with your code.
var computedNumbers : [Double] = Array() 
for i in 0...numbers.count-1 {computedNumbers[i] = Double(numbers[i])*Double(numbers[i])}
print(computedNumbers)

当我尝试 运行 swift 代码时，它给了我以下错误：致命错误：索引超出范围。 我正在尝试通过将 numbers 数组中的每个元素乘以自身来重现 double 数组。

Answer 1

您的 computedNumbers 数组是空的，您正试图访问空的 for 循环中的 computedNumbers[i] 值。如果你想在其中添加数据，试试这个：

var numbers = [45, 73, 195, 53]

//Write your code here
 //Replace this comment with your code.
var computedNumbers : [Double] = []
for i in 0...numbers.count-1 {
  let num = Double(numbers[i])*Double(numbers[i])
  computedNumbers.append(num)
} 
print(computedNumbers)