javascript - 获取数组数组中的列

Question

给定一个 JavaScript 数组:

var m = someNumber;
var n = someOtherNumber;
var myArray = // new m x n Array;

从数组中获取列(而不是行)的最快方法是什么？

前结构:

getColumn = function(anArray, columnNumber){
    //if( column number exists in array)
        //get column
    //else
        //return null
}

Answer 1

就“最少代码”而言，“最快”可能是 Array.prototype.map :

const getColumn = (anArray, columnNumber) =>
    anArray.map(row => row[columnNumber]);

const getColumn = (anArray, columnNumber) =>
    anArray.map(row => row[columnNumber]);


const arr = [
    [1, 2, 3, 4],
    [5, 6, 7, 8],
    [9, 10, 11, 12],
];

console.log(getColumn(arr, 0));