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

Question

Let\'s say there are two arrays...

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

I\'d like the result of the compar

Answer 1

Solution for Swift 4.1/Xcode 9.4:

extension Array where Element: Equatable {
    func containSameElements(_ array: [Element]) -> Bool {
        var selfCopy = self
        var secondArrayCopy = array
        while let currentItem = selfCopy.popLast() {
            if let indexOfCurrentItem = secondArrayCopy.index(of: currentItem) {
                secondArrayCopy.remove(at: indexOfCurrentItem)
            } else {
                return false
            }
        }
        return secondArrayCopy.isEmpty
    }
}

The main advantage of this solution is that it uses less memory than other (it always creates just 2 temporary arrays). Also, it does not require for Element to be Comparable, just to be Equatable.