swift - 具有单个元素的元组

Question

我有以下语法，用于具有单个值的元组

let http200Status = (statusCode: 200, description: "OK")
print("The status code is \(http200Status.statusCode)")

// Prints "The status code is 200"

现在，如果我将个人值(value)更改为

    let http200Status = (Code: 200, Code: "OK")
    print("The status code is \(http200Status.0)"). // 200
    print("The status code is \(http200Status.1)"). // 0k

    print("The status code is \(http200Status.Code)") // it prints 200
    print("The status code is \(http200Status.Code)") // it prints 200 always why not value Ok

我的问题:为什么它总是取 Code 的第一个值？不是第二？

Answer 1

接受同名元组标签是一个错误 (SR-8974)。它已在 Swift 5.1 中修复。来自CHANGELOG :

Duplicate tuple element labels are no longer allowed, because it leads to incorrect behavior.

Xcode 11(测试版 6)正确地提示:

let http200Status = (Code: 200, Code: "OK")
// Error: Cannot create a tuple with a duplicate element label