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

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;
}

其他回答

// Create a places array which holds the index for each item in the
// passed in array.
// 
// Then return a new array by randomly selecting items from the
// passed in array by referencing the places array item. Removing that
// places item each time though.
function shuffle(array) {
    let places = array.map((item, index) => index);
    return array.map((item, index, array) => {
      const random_index = Math.floor(Math.random() * places.length);
      const places_value = places[random_index];
      places.splice(random_index, 1);
      return array[places_value];
    })
}

随机化数组

 var arr = ['apple','cat','Adam','123','Zorro','petunia']; 
 var n = arr.length; var tempArr = [];

 for ( var i = 0; i < n-1; i++ ) {

    // The following line removes one random element from arr 
     // and pushes it onto tempArr 
     tempArr.push(arr.splice(Math.floor(Math.random()*arr.length),1)[0]);
 }

 // Push the remaining item onto tempArr 
 tempArr.push(arr[0]); 
 arr=tempArr; 
var shuffle = function(array) {
   temp = [];
   originalLength = array.length;
   for (var i = 0; i < originalLength; i++) {
     temp.push(array.splice(Math.floor(Math.random()*array.length),1));
   }
   return temp;
};

费希尔·耶茨在javascript中洗牌。我在这里发表这篇文章是因为与这里的其他答案相比,使用两个实用函数(swap和randInt)澄清了算法。

function swap(arr, i, j) { 
  // swaps two elements of an array in place
  var temp = arr[i];
  arr[i] = arr[j];
  arr[j] = temp;
}
function randInt(max) { 
  // returns random integer between 0 and max-1 inclusive.
  return Math.floor(Math.random()*max);
}
function shuffle(arr) {
  // For each slot in the array (starting at the end), 
  // pick an element randomly from the unplaced elements and
  // place it in the slot, exchanging places with the 
  // element in the slot. 
  for(var slot = arr.length - 1; slot > 0; slot--){
    var element = randInt(slot+1);
    swap(arr, element, slot);
  }
}

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