javascript - 有没有办法随机打乱数组，以便数组每次都可以不同地出现？

Question

var arr = [1, 2, 3, 4];
finalarr = [];
for (i = 0; i <= 5; i++) {
  arr.sort(function(a, b) {
    return 0.5 - Math.random();
  });
  finalarr.push(arr);
}
/*once it randomizes that first array, it keeps repeating it. i dont want 
that i want it to reshuffle the array everytime i run that loop*/
console.log(finalarr);

它仅随机化数组一次并不断重复

Answer 1

编辑

第二个演示是演示 1 修改为接受两个参数:

@Params: array [Array]...: The array to shuffle
        repeat [Number]..: The number of new randomized arrays to be returned

@Return: An array of arrays (aka "two-dimensional array") 

---

正如Nick Parsons所述，您使用的是对数组的引用，加上您的结果是一个完整数组，您在其中添加到一个空数组(例如 [[4, 3, 2, 1]]) return 将只是一个与原始数组具有相同元素但顺序随机的数组 ([2, 4, 1, 3])。

以下演示:

1. 使用最有效的方式来打乱数组:Fisher–Yates algorithm .

2. 接受标准数组并通过 spread operator 克隆它[...数组]

3. shuffle() 函数被单独调用三次，并返回一个具有随机顺序的新数组。

注意:有一个可选的实用程序功能，可以更好地显示控制台日志。这不是一个要求。

演示 1

let array = [1, 2, 3, 'A', 'B', 'C'];

const shuffle = ([...array]) => {
  let i = 0;
  let j = 0;
  let temp = null;

  for (i = array.length - 1; i > 0; i -= 1) {
    j = Math.floor(Math.random() * (i + 1));
    temp = array[i];
    array[i] = array[j];
    array[j] = temp;
  }
  return array;
}

const log = data => console.log(JSON.stringify(data));

log(shuffle(array));
log(shuffle(array));
log(shuffle(array));

---

演示 2

let array = [1, 2, 3, 'A', 'B', 'C'];

const shuffle = (array, repeat = 1) => {
  let result = [];
  for (let r = repeat; r > 0; r -= 1) {
    let clone = [...array];
    for (let i = clone.length - 1; i > 0; i -= 1) {
      let s = Math.floor(Math.random() * (i + 1));
      let temp = clone[i];
      clone[i] = clone[s];
      clone[s] = temp;
    }
    result.push(clone);
  }
  return result;
}

const log = data => console.log(JSON.stringify(data));


log(shuffle(array));
log(shuffle(array, 5));
// .flat() is invoked on the return array to provide a single array
log(shuffle(array, 5).flat());