js随机抽取数组

function getRandomElement(arr) {
  if (arr.length === 0) {
    return undefined; // 数组为空时返回undefined
  }
  const randomIndex = Math.floor(Math.random() * arr.length);
  return arr[randomIndex];
}

// 示例用法
const myArray = [1, 2, 3, 4, 5];
const randomElement = getRandomElement(myArray);
console.log(randomElement);

function getRandomElements(arr, count) {
  if (count > arr.length) {
    throw new Error('抽取数量不能大于数组长度');
  }
  const shuffled = arr.slice(); // 创建数组副本
  for (let i = shuffled.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
  }
  return shuffled.slice(0, count);
}

// 示例用法
const myArray = [1, 2, 3, 4, 5];
const randomElements = getRandomElements(myArray, 3);
console.log(randomElements);