如果模式匹配多个案例怎么办? [英] How to do if pattern matching with multiple cases?

问题描述

我正在寻找在 if case 语句中对多个 case 进行模式匹配的语法.示例如下:

I'm searching for the syntax to do pattern matching with multiple cases in an if case statement. The example would be this:

enum Gender {
    case Male, Female, Transgender
}

let a = Gender.Male

现在我想检查一下，a 是 .Male 还是 .Female.但我想避免为此使用 switch.但是 switch 语句会是这样的:

Now I want to check, if a is .Male OR .Female. But I would like to avoid using switch for this. However the switch statement would be like this:

switch a {
case .Male, .Female:
    // do something
}

可以用 if case 写这个吗?我会期待这个，但它没有用:(

Is it possible to write this with if case? I would expect this, but it didn't work :(

if case .Male, .Female = a {

}

推荐答案

一个简单的数组就能解决问题:

A simple array does the trick:

if [.Male, .Female].contains(a) {
    print("Male or female")
} else {
    print("Transgender")
}

我只是对 Swift 推断类型的能力感到惊讶.在这里，它得到 .Male 和 .Female 是来自 a 的性别类型.

I'm simply amazed at Swift's ability to infer type. Here, it gets that .Male and .Female are of type gender from a.

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