快速检查一个数组是否包含另一个数组的元素 [英] Check if an array contains elements of another array in swift

问题描述

我需要检查一个数组是否至少包含另一个数组的一个或多个元素，并迅速将它们打印出来.这是我的情况:

I need to check if an array contains at least one or more elements of another array and print them out in swift. This is my situation:

var array1 = ["user1", "user2", "user3", "user4"]
var array2 = ["user3, "user5", "user7", "user9, "user4"]

//I need to get back an array that says that both the arrays contains ex. "user3" and "user4"

我在网上搜索，但只找到了相反的答案，该问题有助于使用 array.symmetricDifference()

I searched the web but i only found the opposite answer that helps t check if there is a difference between 2 arrays using array.symmetricDifference()

有什么帮助吗???谢谢

Any helps??? Thanks

推荐答案

您可以简单地从第一个集合中创建一个集合，并使其与另一个集合相交:

You can simply create a set from your first collection and get its intersection with the other collection:

let array1 = ["user1", "user2", "user3", "user4"]
let array2 = ["user3", "user5", "user7", "user9", "user4"]
let intersection = Array(Set(array1).intersection(array2)) // ["user4", "user3"] 

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请注意，结果集合的顺序是不可预测的.如果您想保留第一个集合的顺序，则可以创建第二个集合的集合并过滤无法插入其中的元素:

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Note that the order of the resulting collection is unpredictable. If you would like to preserve the order of the first collection you can create a set of the second collection and filter the elements that cannot be inserted to it:

var set = Set(array2)
let intersection = array1.filter { !set.insert($0).inserted }  // ["user3", "user4"]

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您还可以在RangeReplaceableCollection上创建自己的交集方法:

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You can also create your own intersection method on RangeReplaceableCollection:

extension RangeReplaceableCollection {
    func intersection<S: Sequence>(_ sequence: S) -> Self where S.Element == Element, Element: Hashable {
        var set = Set(sequence)
        return filter { !set.insert($0).inserted }
    }
}

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用法:

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Usage:

let intersection = array1.intersection(array2)  // ["user3", "user4"]

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