KCD/SequenceExtensions.swift

   1 //
   2 //  SequenceExtensions.swift
   3 //  KCD
   4 //
   5 //  Created by Hori,Masaki on 2018/08/05.
   6 //  Copyright © 2018年 Hori,Masaki. All rights reserved.
   7 //
   8
   9 import Foundation
  10
  11 // powered by http://stackoverflow.com/questions/40579554/how-to-display-unique-elements-of-an-array-using-swift
  12 extension Sequence where Element: Hashable {
  13
  14     func unique() -> [Element] {
  15
  16         var alreadyAdded = Set<Element>()
  17
  18         return filter {
  19
  20             if alreadyAdded.contains($0) {
  21
  22                 return false
  23             }
  24
  25             alreadyAdded.insert($0)
  26
  27             return true
  28         }
  29     }
  30 }
  31
  32 extension Sequence {
  33
  34     func noneOp(_ f: (Self) -> Void) -> Self {
  35
  36         f(self)
  37
  38         return self
  39     }
  40 }