从我的数组生成随机值，而不重复自己[重复]

Question

这个问题在这里已有答案：

• JavaScript generate random numbers without repeating 3回答
• How to randomize (shuffle) a JavaScript array? 48回答

let colors = ['blue','red','orange','purple','gray','yellow']
let randomColors = [];

我想将colors数组中的3种随机颜色推送到randomColors中。我不希望任何颜色重复。

看似简单，但我花了几个小时不能让它不重复。谢谢 ！

Answer 1

你可以使用这样的东西：

    let colors = ['blue','red','orange','purple','gray','yellow'];
    let randomColors = [];

    // log our initial output
    console.log ( "colors: " + colors );
    console.log ( "randomColors: " + randomColors );

    // this is the loop that pulls colors out of the colors array at random and assigns them to the randomColors array
    // this function is destructive on the colors array, so copy it first if you want to keep the array intact
    // The iterations var can be changed to however many you like, but it will fail if you specify a number larger
    // than there are colors in the array
    var iterations = 3;
    for ( var i = 0; i < iterations; i++ ) {
        // grab a random color from the initial array
        var item = colors[Math.floor(Math.random()*colors.length)];
        var idx = colors.indexOf(item);
        // add it to the randomColors array
        randomColors[i] = item;
        // remove it from the colors array so it isn't picked again
        colors.splice(idx, 1);
    }

    // log our resultant output for comparison
    console.log ( "colors: " + colors );
    console.log ( "randomColors: " + randomColors );

Answer 2

最简单的方法是在lodash包中使用shuffle函数。 https://lodash.com/docs#shuffle 然后从随机数组中选择所需的颜色数：

const colors = ['blue','red','orange','purple','gray','yellow'];
const selectedColors = _.shuffle(colors).splice(0, 3);  // 3 random colors
console.log(selectedColors);

Answer 3

也许是一个笨拙的工具

function random_num_between(min,max){
  return Math.floor(Math.random()*(max-min+1)+min);
}

function pick_one(list){
  const index = random_num_between(0,list.length-1)
  return list[index]
}

function get_elements_distinct(originList,num){
  const map = {}
  let counter = 0
  while(counter < num){
    const key = pick_one(originList)
    if(map[key] == null){
      counter ++
      map[key] = 1
    }
  }
  return Object.keys(map)
}

然后你可以使用它

let colors = ['blue','red','orange','purple','gray','yellow']
let randomColors = get_elements_distinct(colors,3);

Answer 4

let excludedIndexes = [];
let currentIndex = null;
let colors = ['blue','red','orange','purple','gray','yellow'];
let randomColors = [];

function getNextRandom(max)
{
    return Math.floor(Math.random()*max);
}

function addColors(numColors)
{
    let i = 0;
    randomColors = [];
    excludedIndexes = [];
    while(i < numColors)
    {
        currentIndex = getNextRandom(colors.length);
        while(excludedIndexes.indexOf(currentIndex)!=-1)
        {
            currentIndex = getNextRandom(colors.length);
        }
        randomColors.push(colors[currentIndex]);
        excludedIndexes.push(currentIndex);
        i++;
    }
}
addColors(3);//modifies the randomColors array each time it's called

在浏览器控制台中测试。

不得不修复几行，但这应该工作正常。