我有一个这样的数组:

var arr1 = ["a", "b", "c", "d"];

我如何随机化/打乱它?


当前回答

var shuffledArray = function(inpArr){
    //inpArr - is input array
    var arrRand = []; //this will give shuffled array
    var arrTempInd = []; // to store shuffled indexes
    var max = inpArr.length;
    var min = 0;
    var tempInd;
    var i = 0;

    do{
        //generate random index between range
        tempInd = Math.floor(Math.random() * (max - min));
        //check if index is already available in array to avoid repetition
        if(arrTempInd.indexOf(tempInd)<0){
            //push character at random index
            arrRand[i] = inpArr[tempInd];
            //push random indexes
            arrTempInd.push(tempInd);
            i++;
        }
    }
    // check if random array length is equal to input array length
    while(arrTempInd.length < max){
        return arrRand; // this will return shuffled Array
    }
};

只需将数组传递给函数,然后得到经过洗牌的数组

其他回答

使用ES6功能的现代短内联解决方案:

['a','b','c','d'].map(x => [Math.random(), x]).sort(([a], [b]) => a - b).map(([_, x]) => x);

(出于教育目的)

$=(m)=>控制台日志(m);//----将此方法添加到Array类Array.prototype.shuffle=函数(){return this.sort(()=>.5-Math.random());};$([1,65,87,45101,33,9].shuffle());$([1,65,87,45101,33,9].shuffle());$([1,65,87,45101,33,9].shuffle());$([1,65,87,45101,33,9].shuffle());$([1,65,87,45101,33,9].shuffle());

使用underscore.js库。对于这种情况,方法_.shuffle()很好。以下是该方法的示例:

var _ = require("underscore");

var arr = [1,2,3,4,5,6];
// Testing _.shuffle
var testShuffle = function () {
  var indexOne = 0;
    var stObj = {
      '0': 0,
      '1': 1,
      '2': 2,
      '3': 3,
      '4': 4,
      '5': 5
    };
    for (var i = 0; i < 1000; i++) {
      arr = _.shuffle(arr);
      indexOne = _.indexOf(arr, 1);
      stObj[indexOne] ++;
    }
    console.log(stObj);
};
testShuffle();
Array.prototype.shuffle=function(){
   var len = this.length,temp,i
   while(len){
    i=Math.random()*len-- |0;
    temp=this[len],this[len]=this[i],this[i]=temp;
   }
   return this;
}

使用ES2015,您可以使用此功能:

Array.prototype.shuffle = function() {
  let m = this.length, i;
  while (m) {
    i = (Math.random() * m--) >>> 0;
    [this[m], this[i]] = [this[i], this[m]]
  }
  return this;
}

用法:

[1, 2, 3, 4, 5, 6, 7].shuffle();