如何在Swift中不使用".reverse()"来反转数组? [英] How to reverse array in Swift without using ".reverse()"?

问题描述

我有数组，需要使用for循环而无需Array.reverse方法将其反转.

I have array and need to reverse it without Array.reverse method, only with a for loop.

var names:[String] = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

推荐答案

这是@Abhinav的答案翻译为 Swift 2.2 :

Here is @Abhinav 's answer translated to Swift 2.2 :

var names: [String] = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

var reversedNames = [String]()

for arrayIndex in (names.count - 1).stride(through: 0, by: -1) {
    reversedNames.append(names[arrayIndex])
}

使用此代码不应为您提供关于不赞成使用C样式for循环或使用--的任何错误或警告.

Using this code shouldn't give you any errors or warnings about the use deprecated of C-style for-loops or the use of --.

快捷键3-当前:

let names: [String] = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

var reversedNames = [String]()

for arrayIndex in stride(from: names.count - 1, through: 0, by: -1) {
    reversedNames.append(names[arrayIndex])
}

或者，您可以正常遍历并每次减去:

Alternatively, you could loop through normally and subtract each time:

let names = ["Apple", "Microsoft", "Sony", "Lenovo", "Asus"]

let totalIndices = names.count - 1 // We get this value one time instead of once per iteration.

var reversedNames = [String]()

for arrayIndex in 0...totalIndices {
    reversedNames.append(names[totalIndices - arrayIndex])
}

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