Javascript：从数组中随机选择多个元素（不是单个值选择）[重复]

Question

我正在尝试编写代码以从数组中选择 n 个随机元素。例如：

const originalArray = ["a", "b", "c", "d", "e", "f", "g", "h", "i"];

const randomSelection = (n) => {
    if (n > originalArray.length) {
        return originalArray;
    } else {
        //Some Code to randomly select n elements from orignialArray
    }
}

const newArray = randomSelection(2); //Random selection of 2 elements from the above array

实现此目的的代码是什么？我搜索了案例，但想知道是否有更简单、更直接的方法来做到这一点。

有什么建议吗？提前非常感谢！

Answer 1

此代码从数组中生成n 随机元素，并避免重复：

const originalArray = ["a", "b", "c", "d", "e", "f", "g", "h", "i"];

const randomSelection = (n) => {
  let newArr = [];
  if (n >= originalArray.length) {
    return originalArray;
  }
  for (let i = 0; i < n; i++) {
    let newElem = originalArray[Math.floor(Math.random() * originalArray.length)];
    while (newArr.includes(newElem)) {
      newElem = originalArray[Math.floor(Math.random() * originalArray.length)];
    }
    newArr.push(newElem);
  }
  return newArr;
}

console.log(randomSelection(2));
console.log(randomSelection(5));

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如果您不关心重复，请删除while：

const originalArray = ["a", "b", "c", "d", "e", "f", "g", "h", "i"];

const randomSelection = (n) => {
  let newArr = [];
  if (n >= originalArray.length) {
    return originalArray;
  }
  for (let i = 0; i < n; i++) {
    let newElem = originalArray[Math.floor(Math.random() * originalArray.length)];
    newArr.push(newElem);
  }
  return newArr;
}

console.log(randomSelection(2));
console.log(randomSelection(5));

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Answer 2

你可以做类似的事情

let randArr = [];
while(let i = 0; i < n; i++)
     let chosen = Math.floor(Math.random() *  originalarray.length);

     randArr[i] = originalarray[chosen];
}
return randArr;

那么你可以从数组中检索多个随机值。

Answer 3

试试这个：

const originalArray=["a","b","c","d","e","f","g","h","i"];


function RandomElements(n){
  const newArray = []

    if (n>originalArray.length) {
        return originalArray;
    }
    else {
      for(let i = 0; i < n; i++){
    newArray.push(originalArray[Math.floor(Math.random() * originalArray.length)])
  }
  return newArray;
    }

}

console.log(RandomElements(2))

Answer 4

function randArr(n) {
    let ta = arr, i=0;
    while(i<n) {
        let ri = Math.floor(Math.random()*ta.length);
        ta[i] = [ta[ri], ta[ri]=ta[i]][0];
        i++;    
    }
    ta.splice(i, ta.length);
    return ta;
}

选择随机时，数组元素不会重复。