arraysswiftswift2

How do I check in Swift if two arrays contain the same elements regardless of the order in which those elements appear in?

Let's say there are two arrays...

var array1 = ["a", "b", "c"]
var array2 = ["b", "c", "a"]

I'd like the result of the comparison of these two arrays to be true, and the following...

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

...to be false. How can I achieve that in Swift? I tried to convert both arrays to sets but for some reason Set() keeps removing some (usually duplicated) objects that the array contains.

Any help would be appreciated.

Solution

  • Swift 3, 4

    extension Array where Element: Comparable {
    func containsSameElements(as other: [Element]) -> Bool {
        return self.count == other.count && self.sorted() == other.sorted()
    }
}

// usage
let a: [Int] = [1, 2, 3, 3, 3]
let b: [Int] = [1, 3, 3, 3, 2]
let c: [Int] = [1, 2, 2, 3, 3, 3]

print(a.containsSameElements(as: b)) // true
print(a.containsSameElements(as: c)) // false