小编sab*_*abi的帖子

写一个 randomStringGenerator() 函数，我想出了这个：

private let characters = ("0123456789" + "abcdefghijklmnopqrstuvwxyz" +
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ").characters.map{ $0 }

private func generateRandomChar() -> Character {
  let index = Int( arc4random_uniform( UInt32( characters.count)))
  return characters[index]
}

func generateRandomString(lenght: Int) -> String {
  var string = ""
  for _ in 0..<lenght {
    string.append(generateRandomChar())
  }
  return string
}

请注意我使用的第二行"0123...".characters.map{$0}，我对这个（工作）语法的使用感到困惑。绘制地图而不执行任何操作是什么意思？是否有用于相同目的的更解释性语法？

从stackoverflow上的Simple C程序开始,我在Swift中再次完成了这个代码:

import Foundation

// variables and constants:

var dice1, dice2: UInt32
var score, scoreToWin, diceSum: Int
dice1 = 0
dice2 = 0
diceSum = 0

// functions:

func rollDice() ->Int {
  dice1 = arc4random() % 6 + 1
  dice2 = arc4random() % 6 + 1
  diceSum = Int(dice1 + dice2)
  println("\(diceSum)")
  return diceSum
}

// main:

score = rollDice()

println("\(dice1) \(dice2) \(score)")

switch score {
  case 7, 11:
    println("score=\(score)\nYou WIN")
  case 2, 3, 12:
    println("score=\(score)\nYou LOOSE")
  default: …