javascript - 从一维数组创建二维数组

Question

我是编程新手，我有一个作业要求从一维数组创建二维数组。我想出了这个(没有任何外部来源的帮助，因为它剥夺了学习经验)。它适用于我们的教授测试输入，我只是想知道这是一个丑陋/低效的解决方案。

function twoDArray(arr, lenSubArray) {
    var newArr = []; 
    var placeHolder = 0; 
    var leftOver = 0; 
    for (var i = 1; i < arr.length + 1; i++) {
        /* if i is a multiple of the specified sub-array size 
           then add the elements from placeHolder to i
        */
        if (i % lenSubArray === 0) {
            newArr.push(arr.slice(placeHolder, i)); 
            placeHolder += lenSubArray; 
            leftOver++; // tells us how many sub-arrays were created
        }
    }
    /* if original array is not divisible by the length of the specified sub-array
       then there will be left over values. Retrieve these values and create an 
       array out of them and add them to the 2d array.
    */
    if (!(arr.length % lenSubArray === 0)) {
         /* sub-array count multiplied by the length of each 
            sub-array gives us the right index to retrieve remaining values
        */
        leftOver = (leftOver * lenSubArray);
        newArr.push(arr.slice(leftOver))
    }

    return newArr; 
}

测试输入:twoDArray([1, 2, 3, 4, 5], 3) 输出将是: [[1, 2, 3], [4, 5]]

Answer 1

你太复杂了:

• 创建结果数组
• 将切片从 i 推送到 i+lenSubArray
• 将i增加lenSubArray

切片足够智能，可以正确处理数组的末尾

function twoDArray(arr, lenSubArray) {
  var i = 0, result = [];
  while(i < arr.length)
    result.push( arr.slice(i, i+=lenSubArray) );
  return result;  
}