sampleSize

2024年06月17日

柏拉文

越努力，越幸运

一、认识

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从 collection（集合）中获得 n 个随机元素。

二、语法

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三、实现

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function sampleSize(array, n) {
  let nCopy = n == null ? 1 : n;
  const length = array == null ? 0 : array.length;
  if (length == 0 || nCopy < 1) {
    return [];
  }
  nCopy = nCopy > length ? length : n;
  let index = -1;
  const lastIndex = length - 1;
  const result = [...array];
  while (++index < nCopy) {
    const rand = index + Math.floor(Math.random() * (lastIndex - index + 1));
    const value = result[rand];
    result[rand] = result[index];
    result[index] = value;
  }
  return result.slice(0, n);
}

console.log(sampleSize([1, 2, 3], 1));