在阵列

Question

func randomStringWithLength (len : Int) -> NSString { 

    let answer : NSString = ArrAnswer.objectAtIndex(0) as! NSString 
    let letters : NSString = answer 
    print(letters) 
    let randomString : NSMutableString = NSMutableString(capacity: len) 

    for (var i=0; i < len; i++){ 
     let length = UInt32 (letters.length) 
     let rand = arc4random_uniform(length) 
     randomString.appendFormat("%C", letters.characterAtIndex(Int(rand))) 

    } 

    return randomString 
} 

的索引创建随机字符串我已经尝试此， 一些后者缺少在每次转换后的字符串或一段时间内打印一后两次或三次的时间。

Answer 1

我不知道究竟你需要的。如果你需要在随机字符串中的字符，你可以使用类似这样

import Foundation 
let str = "abcdef" 

// returns string with random order of characters 
func randomize(str: String)->String { 
    var chars = str.characters.map{ $0 } 
    let c = UInt32(chars.count) 
    if c < 2 { return str} 

    for i in 0..<(c - 1) { 
     let j = arc4random_uniform(c) 
     if i != j { 
      swap(&chars[Int(i)], &chars[Int(j)]) 
     } 
    } 
    return chars.reduce("", combine: { (str, c) -> String in 
     str + String(c) 
    }) 
} 
for i in 0...10 { 
    print(randomize(str)) 
} 
/* prints 

dcbeaf 
edcabf 
cebadf 
adcbef 
dacbef 
dceabf 
eacbdf 
adebcf 
adcbef 
bedcaf 
daebcf 

*/ 

Answer 2

我觉得这是做的最好办法，除非otherone有另外一种方法，你可能需要适应此代码为您necesities：

let array = ["Frodo", "sam", "wise", "gamgee"] 
let randomIndex = Int(arc4random_uniform(UInt32(array.count))) 
print(array[randomIndex])