在 Swift 数组上设置操作(联合、交集)? [英] Set operations (union, intersection) on Swift array?

问题描述

是否有任何标准库调用可用于对两个数组执行设置操作，或自己实现此类逻辑(理想情况下，功能和效率尽可能高)?

Are there any standard library calls I can use to either perform set operations on two arrays, or implement such logic myself (ideally as functionally and also efficiently as possible)?

推荐答案

是的，Swift 有 Set 类.

Yes, Swift has the Set class.

let array1 = ["a", "b", "c"]
let array2 = ["a", "b", "d"]

let set1:Set<String> = Set(array1)
let set2:Set<String> = Set(array2)

Swift 3.0+ 可以对集合进行操作:

Swift 3.0+ can do operations on sets as:

firstSet.union(secondSet)// Union of two sets
firstSet.intersection(secondSet)// Intersection of two sets
firstSet.symmetricDifference(secondSet)// exclusiveOr

Swift 2.0 可以计算数组参数:

Swift 2.0 can calculate on array arguments:

set1.union(array2)       // {"a", "b", "c", "d"} 
set1.intersect(array2)   // {"a", "b"}
set1.subtract(array2)    // {"c"}
set1.exclusiveOr(array2) // {"c", "d"}

Swift 1.2+ 可以在集合上进行计算:

Swift 1.2+ can calculate on sets:

set1.union(set2)        // {"a", "b", "c", "d"}
set1.intersect(set2)    // {"a", "b"}
set1.subtract(set2)     // {"c"}
set1.exclusiveOr(set2)  // {"c", "d"}

如果您使用自定义结构，则需要实现 Hashable.

If you're using custom structs, you need to implement Hashable.

感谢 Michael Stern 对 Swift 2.0 更新的评论.

Thanks to Michael Stern in the comments for the Swift 2.0 update.

感谢 Amjad Husseini 对 Hashable 信息的评论.

Thanks to Amjad Husseini in the comments for the Hashable info.

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