在Swift中为自定义类重载等价（==）运算符 [英] Overloading equivalence (==) operator for custom class in Swift

问题描述

是否可以为该自定义类中的自定义类重载等价（==）运算符。但是我知道可以让这个运算符在类范围外重载。感谢任何示例代码。
提前致谢。

Is it possible to overload equivalence (==) operator for a custom class inside that custom class. However I know that it is possible to have this operator overloaded outside class scope. Appreciate any sample code. Thanks in advance.

推荐答案

添加全局功能。例如：

class CustomClass {
    var id = "my id"
}

func ==(lhs: CustomClass, rhs: CustomClass) -> Bool {
    return lhs == rhs
}
func !=(lhs: CustomClass, rhs: CustomClass) -> Bool {
    return !(lhs == rhs)
}

符合Swift 2中的Equatable协议

To conform Equatable protocol in Swift 2

class CustomClass: Equatable {
    var id = "my id"
}

func ==(left: CustomClass, right: CustomClass) -> Bool {
    return left.id == right.id
}

To符合Swift 3中的Equatable协议

To conform Equatable protocol in Swift 3

class CustomClass {
    var id = "my id"
}

extension CustomClass: Equatable {
    static func ==(lhs: CustomClass, rhs: CustomClass) -> Bool {
        return lhs.id == rhs.id
    }
}

这篇关于在Swift中为自定义类重载等价（==）运算符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！