我想在JavaScript中打乱一个元素数组,如下所示:
[0, 3, 3] -> [3, 0, 3]
[9, 3, 6, 0, 6] -> [0, 3, 6, 9, 6]
[3, 3, 6, 0, 6] -> [0, 3, 6, 3, 6]
发布于 2011-06-08 12:58:38
使用the modern version of the Fisher–Yates shuffle algorithm
/**
* Shuffles array in place.
* @param {Array} a items An array containing the items.
*/
function shuffle(a) {
var j, x, i;
for (i = a.length - 1; i > 0; i--) {
j = Math.floor(Math.random() * (i + 1));
x = a[i];
a[i] = a[j];
a[j] = x;
}
return a;
}
ES2015 (ES6)版本
/**
* Shuffles array in place. ES6 version
* @param {Array} a items An array containing the items.
*/
function shuffle(a) {
for (let i = a.length - 1; i > 0; i--) {
const j = Math.floor(Math.random() * (i + 1));
[a[i], a[j]] = [a[j], a[i]];
}
return a;
}
然而,请注意,从2017年10月起,与destructuring assignment交换变量会导致显著的性能损失。
使用
var myArray = ['1','2','3','4','5','6','7','8','9'];
shuffle(myArray);
实现原型
使用Object.defineProperty
(method taken from this SO answer),我们还可以将此函数实现为数组的原型方法,而不会在for (i in arr)
等循环中显示它。下面的代码将允许您调用arr.shuffle()
来混洗数组arr
Object.defineProperty(Array.prototype, 'shuffle', {
value: function() {
for (let i = this.length - 1; i > 0; i--) {
const j = Math.floor(Math.random() * (i + 1));
[this[i], this[j]] = [this[j], this[i]];
}
return this;
}
});
发布于 2011-06-08 13:01:40
您可以使用Fisher-Yates Shuffle (改编自this site的代码):
function shuffle(array) {
let counter = array.length;
// While there are elements in the array
while (counter > 0) {
// Pick a random index
let index = Math.floor(Math.random() * counter);
// Decrease counter by 1
counter--;
// And swap the last element with it
let temp = array[counter];
array[counter] = array[index];
array[index] = temp;
}
return array;
}
https://stackoverflow.com/questions/6274339
复制相似问题