如何从JavaScript中以前未选择的数组中随机选择一个元素? [英] How to Randomly Choose an Element from an Array that Wasn't Chosen before in JavaScript?

问题描述

我想运行一个函数，每次随机从以前未选择的数组中随机选择一个元素.如果所有元素都被选中，我想重置使用过的元素并从头开始.

I want to run a function that each time randomly chooses an element from an array that wasn't chosen before. And if all elements were chosen, I want to reset the used elements and start from the beginning.

希望这是有道理的.

我已经有了一个从数组中选择随机元素的函数.但是我也不希望它选择以前选择的元素，除非所有元素都已被选择.

I already have a function that chooses a random element from an array. But I also don't want it to choose elements that were chosen before unless all elements were already chosen.

这是我到目前为止所获得的(贷记@Kelly):

Here is what I have got so far (credit to @Kelly):

var item = items[Math.floor(Math.random() * items.length)]

推荐答案

您可以尝试执行以下操作:

You can try something like this:

• 创建一个实用函数，该函数接受一个数组并返回一个随机值.
• 在此数组内，维护2个数组，选择和数据.
• 在每次迭代中，从 data 中删除一项，并将其放入 chosenItems
• 一旦 data 的长度达到 0 ，将 chosenItems 或 originalArray 设置为数据并重复处理./li>

• Create a utility function that takes an array and returns you a random value.
• Inside this Array, maintain 2 array, choices and data.
• In every iteration, remove 1 item from data and put it in chosenItems
• Once the length of data reaches 0, set chosenItems or originalArray as data and repeat process.

这种方法的好处是，

• 您不需要维护和传递数组变量.
• 可以使其通用并多次使用.

function randomize(arr) {
  let data = [...arr];
  let chosenItems = [];

  function getRandomValue() {
    if (data.length === 0) {
      data = chosenItems;
      chosenItems = [];
    }
    const index = Math.floor(Math.random() * data.length);
    const choice = data.splice(index, 1)[0];

    chosenItems.push(choice);
    return choice;
  }
  
  return {
    randomItem: getRandomValue
  }
}

const dummyData = [ 1,2,3,4,5 ];

const randomizeData = randomize(dummyData);

for (let i = 0; i< 10; i++) {
  console.log(randomizeData.randomItem())
}

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