检查一个范围是否在另一个范围内 [英] Check if one Range is within another

问题描述

let smallRange = 1..<2
let largeRange = 0..<10
largeRange ~= smallRange // False

为什么要先编译这个！?
但如果它编译，答案应该是 True

Why does this compile at the first place!?
But if it compiles the answer should be True

下一个代码有效:

smallRange.clamped(to: largeRange) == smallRange // True

有没有更简单的检查方法?

Is there any simpler way to check?

推荐答案

我不认为你会找到一个更简单"的或更短"写这个的方式，但你可以定义你自己的模式匹配运算符来缩短你的代码:

I don't think you will find a "simpler" or "shorter" way of writing this but you can define your own pattern matching operator to shorten your code:

extension Range {
    static func ~=(lhs: Self, rhs: Self) -> Bool {
        rhs.clamped(to: lhs) == rhs
    }
}

---

extension ClosedRange {
    static func ~=(lhs: Self, rhs: Self) -> Bool {
        rhs.clamped(to: lhs) == rhs
    }
}

---

let smallRange = 1..<2
let largeRange = 0..<10
smallRange ~= largeRange // false
largeRange ~= smallRange // true

注意:它编译是因为有一个通用实现用于检查相等性，例如切换字符串，因此只有在两个范围相同时它才会返回 true.

Note: It compiles because there is a generic implementation used to check for equality like switching a string therefore it would only return true if both ranges were the same.

func ~= <T>(a: T, b: T) -> Bool where T : Equatable

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