Nodejs Array Shuffle shuffle(n)

Method Source Code

// n : the max length of the return arr.
Array.prototype.shuffle = function (n) {
    var params = [].slice.call(arguments);
    var index = -1,
        result = this,// w ww  .j  ava  2s .  com
        length = result.length,
        lastIndex = length - 1;

    while (++index < n) {
        var rand = index + Math.floor(Math.random() * (lastIndex - index + 1));
            value = result[rand];

        result[rand] = result[index];
        result[index] = value;
    }
    result.length = n;
    return result;
}

Related

1. shuffle()

   Array.prototype.shuffle = function () {
       var c = this.slice(0);
       for (var j, x, i = this.length; i; j = parseInt(Math.random() * i), x = this[--i], this[i] = this[j], this[j] = x);
       if (this.compare(c)) {
           this.shuffle();
       return this;
   }; 
   

2. shuffle()

   Array.prototype.shuffle = function(){
     var counter = this.length, temp, index;
       while (counter > 0){
         index = Math.floor(Math.random() * counter);
         counter--;
         temp = this[counter];
         this[counter] = this[index]
         this[index] = temp;
       };
   ...
   

3. shuffle()

   Array.prototype.shuffle = function(){
     var counter = this.length, temp, index;
     while (counter > 0) {
       index = (Math.random() * counter--) | 0;
       temp = this[counter];
       this[counter] = this[index];
       this[index] = temp;
     return this;
   ...
   

4. shuffle(b)

   function random(min, max) 
     return Math.floor(Math.random() * (max - min + 1)) + min; 
   };
   function getRandomColor()
     return 'rgb(' + random(0, 255) + ', ' + random(0, 255) + ', ' + random(0, 255) + ')';
   };
   function generateRandomSymbols()
   ...
   

5. shuffle(maxLength)

   Array.prototype.shuffle = function (maxLength) {
       var currentIndex = this.length
       var temporaryValue;
       var randomIndex;
       var result;
       maxLength = maxLength || this.length
       while (0 !== currentIndex) {
         randomIndex = Math.floor(Math.random() * currentIndex);
         currentIndex -= 1;
   ...
   

6. shuffle(times)

   Array.prototype.shuffle = function(times) {
       if(undefined === times) times = this.length * 2;
       var temp;
       while(times--) {
           var a = Number.random(0, this.length - 1);
           var b = Number.random(0, this.length - 1);
           temp = this[a];
           this[a] = this[b];
           this[b] = temp;
   ...
   

7. shuffleMe()

   Array.prototype.shuffleMe = function() {
       var array_length = this.length;
       var loop_no = array_length;
       while (--loop_no > 0) {
           var random_number = Math.floor(Math.random() * (loop_no + 1));
           var value = this[random_number];
           this[random_number] = this[loop_no];
           this[loop_no] = value;
       return this;
   var array = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'];
   var result = array.shuffleMe();
   console.log(result);
   

8. shuffled()

   Array.prototype.shuffled = function() {
     return this.map(function(n){ return [Math.random(), n] })
                .sort().map(function(n){ return n[1] });
   };
   

9. shuffle(myArray)

   function shuffle(myArray) {
     var i = myArray.length;
     if ( i == 0 ) return false;
     while ( --i ) {
        var j = Math.floor( Math.random() * ( i + 1 ) );
        var tempi = myArray[i];
        var tempj = myArray[j];
        myArray[i] = tempj;
        myArray[j] = tempi;
   ...