javascript - 数组元素不拼接成单独的数组 - FreeCodeCamp > Chunky Monkey

Question

我正在应对 FreeCodeCamp 挑战，但遇到了以下挑战:

Our goal for this Algorithm is to split arr (first argument) into smaller chunks of arrays with the length provided by size (second argument). There are several green checks (objectives) our code needs to pass in order to complete this Algorithm:

(['a', 'b', 'c', 'd'], 2) is expected to return [['a', 'b'], ['c', 'd']]

([0, 1, 2, 3, 4, 5], 3) is expected to return [[0, 1, 2], [3, 4, 5]]

([0, 1, 2, 3, 4, 5], 2) is expected to return [[0, 1], [2, 3], [4, 5]]

([0, 1, 2, 3, 4, 5], 4) is expected to return [[0, 1, 2, 3], [4, 5]]

([0, 1, 2, 3, 4, 5, 6, 7, 8], 2) is expected to return [[0, 1], [2, 3], [4, 5], [6, 7], [8]].

这是我想出的代码:

function chunkArrayInGroups(arr, size) {

  var newArray = [];
  var holdArray = [];
  for (var i = 0; i <= arr.length; i += size) {
    holdArray = arr.slice(0, size);
    removed = arr.splice(0, size);
    newArray.push(holdArray);
  }
  if (arr.length !== 0) {
    newArray.push(arr);
    return newArray;
  }
  else return newArray; 
}

chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 2);

该算法适用于除最后一个目标之外的所有目标。而不是返回:

[[0, 1], [2, 3], [4, 5], [6, 7], [8]]

它正在返回:

[[0, 1], [2, 3], [4, 5], [6, 7, 8]] - 我不知道为什么。

如果能帮助我弄清楚哪里出了问题，我们将不胜感激!

Answer 1

我不怪你一头雾水，我也花了一段时间才找到问题。

首先确定您的 for 循环有点奇怪 - 您没有将 i 变量用于任何事情。此外，您 splice() 每次迭代都将原始数组向下，因此您的意图是正确的 - 等待直到数组中剩余的元素少于 size 。

所以我将其表示为 while 循环，瞧，它有效:

function chunkArrayInGroups(arr, size) {

  var newArray = [];
  var holdArray = [];
  while (arr.length >= size) {
    holdArray = arr.slice(0, size);
    removed = arr.splice(0, size);
    newArray.push(holdArray);
  }
  if (arr.length !== 0) {
    newArray.push(arr);
    return newArray;
  }
  else return newArray; 
}

chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 2);