Removing duplicate elements from an array in Swift

Question

I might have an array that looks like the following:

[1, 4, 2, 2, 6, 24, 15, 2, 60, 15, 6]

Or, reall

Answer 1

edit/update Swift 4 or later

We can also extend RangeReplaceableCollection protocol to allow it to be used with StringProtocol types as well:

extension RangeReplaceableCollection where Element: Hashable {
    var orderedSet: Self {
        var set = Set()
        return filter { set.insert($0).inserted }
    }
    mutating func removeDuplicates() {
        var set = Set()
        removeAll { !set.insert($0).inserted }
    }
}

---

let integers = [1, 4, 2, 2, 6, 24, 15, 2, 60, 15, 6]
let integersOrderedSet = integers.orderedSet // [1, 4, 2, 6, 24, 15, 60]

---

"abcdefabcghi".orderedSet  // "abcdefghi"
"abcdefabcghi".dropFirst(3).orderedSet // "defabcghi"

---

Mutating method:

var string = "abcdefabcghi"
string.removeDuplicates() 
string  //  "abcdefghi"

var substring = "abcdefabcdefghi".dropFirst(3)  // "defabcdefghi"
substring.removeDuplicates()
substring   // "defabcghi"

---

For Swift 3 click here