使用通配符对多个值进行模式匹配 [英] Pattern matching on multiple values with a wildcard

问题描述

在Kotlin中，我们可以使用when对给定值(例如

In Kotlin, we can use when to pattern match on a given value, e.g.,

when(value) {
    1 -> "One"
    2, 3 -> "Two or three"
    else -> "The rest"
}

我们还可以通过将两个值嵌套在Pair中来同时对多个值进行模式匹配.

We can also pattern match on multiple values at the same time by nesting the two values in a Pair.

when(Pair(value1, value2)) {
    (1, "One") -> "One"
    (2, "Two"), (3, "Three") -> "Two or three"
    else -> "The rest"
}

现在，我想知道如何使用通配符同时对多个值进行模式匹配. 我尝试了以下两种方法，但均未成功:

Now, I'd like to know how to pattern match on multiple values at the same time with a wildcard. I tried the following two approaches without success:

when(Pair(value1, value2)) {
    (1, _), (_, "One") -> "One"
    (2, _), (_, "Two"), (3, _), (_, "Three") -> "Two or three"
    else -> "The rest"
}

和

when(Pair(value1, value2)) {
    (1, else), (else, "One") -> "One"
    (2, else), (else, "Two"), (3, else), (else, "Three") -> "Two or three"
    else -> "The rest"
}

如何匹配其中一个变量的大小写?

推荐答案

Kotlin不具备您可能从其他语言中了解到的模式匹配功能.参见此处，对该功能进行讨论: https://discuss.kotlinlang. org/t/destructuring-in-when/2391/18

Kotlin doesn't have the pattern matching capabilities that you might know from other languages. See here for a discussion on the feature: https://discuss.kotlinlang.org/t/destructuring-in-when/2391/18

when不支持您的用例.

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