Javascript 如何实例化并获取多维数组/矩阵的长度？

如何在JavaScript和Typescript中实例化多维数组/矩阵，以及如何获得矩阵长度（行数）和矩阵行的长度？

在Typescript中，您将使用以下语法实例化2x6矩阵/多维数组：

var matrix: number[][] = 
[
    [ -1, 1, 2, -2, -3, 0 ],
    [ 0.1, 0.5, 0, 0, 0, 0 ]
];

 //OR

var matrix: Array<number>[] =
[
    [ -1, 1, 2, -2, -3, 0 ],
    [ 0.1, 0.5, 0, 0, 0, 0 ]
];

JavaScript语法在TypeScript中也有效，因为类型是可选的，但TypeScript语法在JavaScript中无效

要获得不同的长度，可以在JS和TS中使用相同的语法：

var matrixLength = matrix.length; // There are two dimensions, so the length is 2. This is also the column size.
var firstDimensionLength = matrix[0].length; // The first dimension row has 6 elements, so the length is 6
var secondDimensionLength = matrix[1].length; // The second dimension row has 6 elements so the length is 6

我建议使用

number[][]

var matrixLength = matrix.length; // There are two dimensions, so the length is 2. This is also the column size.
var firstDimensionLength = matrix[0].length; // The first dimension row has 6 elements, so the length is 6
var secondDimensionLength = matrix[1].length; // The second dimension row has 6 elements so the length is 6