Comments (3)
Array. prototype.shuffle = function() {
var _self = this;
for (var i = _self.length - 1; i >= 0; i--) {
var random = Math.floor(Math.random() * (i + 1));
var randomItem = _self[random];
_self[random] = _self[i];
_self[i] = randomItem;
}
return _self;
}
[1, 2, 3, 4, 5, 6].shuffle();
from daily.
核心是实现一个伪随机数,最容易想到Math.random ,当然也可以利用数学常用的方法,比如对 -1 取随机的数进行 幂运算,然后和0 比较
有了随机数,就可以对数组操作了,当然每次后都要将渠道的值从原来的数组删掉,同时随机数的范围减去一,为了不对原数组造成印象,所以在最开始之前要拷贝原数组,操作副本
from daily.
洗牌算法
Fisher-Yates洗牌算法也被称为高纳德置乱算法,作用就是生成一个有限集合的随机排序。
代码实现
var arr = [];
for (let i = 0; i < 10; i++) {
arr[i] = i + 1;
}
for (let i = arr.length - 1; i > 0; i--) {
let rand = Math.round(Math.random() * i);
let temp = arr[i];
arr[i] = arr[rand];
arr[rand] = temp;
}
from daily.
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from daily.