javascript - 在 JavaScript 中转置二维数组

Question

我有一个数组数组，类似于:

[
    [1,2,3],
    [1,2,3],
    [1,2,3],
]

我想转置它以获得以下数组:

[
    [1,1,1],
    [2,2,2],
    [3,3,3],
]

使用循环以编程方式执行此操作并不困难:

function transposeArray(array, arrayLength){
    var newArray = [];
    for(var i = 0; i < array.length; i++){
        newArray.push([]);
    };

    for(var i = 0; i < array.length; i++){
        for(var j = 0; j < arrayLength; j++){
            newArray[j].push(array[i][j]);
        };
    };

    return newArray;
}

然而，这看起来很笨重，我觉得应该有一种更简单的方法来做到这一点。有吗？

Answer 1

output = array[0].map((_, colIndex) => array.map(row => row[colIndex]));

map calls a provided callback function once for each element in an array, in order, and constructs a new array from the results. callback is invoked only for indexes of the array which have assigned values; it is not invoked for indexes which have been deleted or which have never been assigned values.

callback is invoked with three arguments: the value of the element, the index of the element, and the Array object being traversed. [source]