我想要一个5个字符的字符串,由从集合[a-zA-Z0-9]中随机选取的字符组成。

用JavaScript实现这一点的最佳方法是什么?


当前回答

function generate(length) {
  var letters = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9"];
  var IDtext = "";
  var i = 0;
  while (i < length) {
    var letterIndex = Math.floor(Math.random() * letters.length);
    var letter = letters[letterIndex];
    IDtext = IDtext + letter;
    i++;
  }
  console.log(IDtext)
}

其他回答

这一个结合了许多给出的答案。

var randNo=Math.floor(Math.random()*100)+2+“”+new Date().getTime()+Math.floof(Math.rrandom()*100)+2+(Math.rand().toString(36).replace(/[^a-zA-Z]+/g,'').substr(0,5));console.log(randNo);

我用了一个月,效果很好。

像这样的东西应该有用

function randomString(len, charSet) {
    charSet = charSet || 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    var randomString = '';
    for (var i = 0; i < len; i++) {
        var randomPoz = Math.floor(Math.random() * charSet.length);
        randomString += charSet.substring(randomPoz,randomPoz+1);
    }
    return randomString;
}

使用默认字符集[a-zA-Z0-9]调用或发送您自己的:

var randomValue = randomString(5);

var randomValue = randomString(5, 'PICKCHARSFROMTHISSET');

这里有一些简单的一行。更改新阵列(5)以设置长度。

包括0-9a-z

new Array(5).join().replace(/(.|$)/g, function(){return ((Math.random()*36)|0).toString(36);})

包括0-9a-zA-Z

new Array(5).join().replace(/(.|$)/g, function(){return ((Math.random()*36)|0).toString(36)[Math.random()<.5?"toString":"toUpperCase"]();});

ES6编码(0-9a-z)

Array(5).fill().map(n=>(Math.random()*36|0).toString(36)).join('')

功能性方法。只有在应用程序的其他部分可以利用功能先决条件时,这个答案才实用。表演可能是垃圾,但写起来非常有趣。

//功能先决条件常量U=f=>f(f)常量Y=U(h=>f=>f(x=>h(h)(f)(x)))常量comp=f=>g=>x=>f(g(x))常量foldk=Y(h=>f=>Y=>([x,…xs])=>x===未定义?y:f(y)(x)(y=>h(f)(y))(xs))常量fold=f=>foldk(y=>x=>k=>k(f(y)(x)))常量映射=f=>fold(y=>x=>[…y,f(x)])([])constchar=x=>String.fromCharCode(x)常量concat=x=>y=>y.concat(x)常量concatMap=f=>comp(fold(concat)([]))(map(f))const irand=x=>数学地板(Math.random()*x)常量样本=xs=>xs[irand(xs.length)]//范围:从x到y的范围;[x…y]//编号->编号->[编号]常量范围=Y(f=>r=>x=>Y=>x>y?r:f([…r,x])(x+1)(y)) ([])//srand:从列表或ascii代码范围生成随机字符串//[(范围a)]->编号->[a]常量srand=comp(Y(f=>z=>rs=>x=>x===0?z:f(z+样本(rs))(rs)(x-1))([]))(concatMap(map(char)))//idGenerator:生成指定长度的标识符//数字->字符串常量idGenerator=srand([范围(48)(57),//包括0-9范围(65)(90),//包括A-Z范围(97)(122)//包括a-z])console.log(idGenerator(6))//=>TT688Xconsole.log(idGenerator(10))//=>SzaaUBlpI1console.log(idGenerator(20))//=>eYAaWhsfvLDhIBID1xRh

在我看来,如果不添加神奇的、做太多事情的功能,很难超越idGenerator的清晰度。

稍有改进

// ord : convert char to ascii code
// Char -> Number
const ord = x => x.charCodeAt(0)

// idGenerator : make an identifier of specified length
// Number -> String
const idGenerator = srand ([
  range (ord('0')) (ord('9')),
  range (ord('A')) (ord('Z')),
  range (ord('a')) (ord('z'))
])

玩得开心。让我知道你喜欢/学习什么^_^

短、简单、可靠

返回5个随机字符,而不是此处找到的一些排名最高的答案。

Math.random().toString(36).slice(2, 7);