英文:
Rotating non square matrix in javascript
问题
我试图找到一种将矩形矩阵旋转90度的方法。
例如：
将这个旋转：
变成这个：
我有一个像这样的索引数组：
array = [0,0,0,0,0,0,1,1,1,0,0,0,0,0,0]
width = 5
height = 3
这是我想要的：
array90 = [0,0,0,0,1,0,0,1,0,0,1,0,0,0,0]
谢谢。
英文:
Im trying to find a way to transform a rectangular matrix by 90 degree.
E.g:
rotate this:
to this:
I got an array of indices like that:
array = [0,0,0,0,0,0,1,1,1,0,0,0,0,0,0];
width = 5;
height = 3;
Thats what I want to get:
array90 = [0,0,0,0,1,0,0,1,0,0,1,0,0,0,0];
Thanks in regard
答案1
得分: 0
在JavaScript中，要将一个矩形矩阵顺时针旋转90度，可以采用以下方法：
首先，通过交换矩阵的行和列来进行矩阵的转置操作。然后，反转行的顺序以获得旋转后的矩阵。
以下是这个方法的实现和一个示例：
// 这个函数以矩形矩阵作为输入，返回旋转后的矩阵
function rotateMatrix(matrix) {
const rows = matrix.length;
const cols = matrix[0].length;
// 转置矩阵
const transposedMatrix = [];
for (let j = 0; j < cols; j++) {
const row = [];
for (let i = 0; i < rows; i++) {
row.push(matrix[i][j]);
}
transposedMatrix.push(row);
}
// 反转行
for (let i = 0; i < cols; i++) {
transposedMatrix[i].reverse();
}
return transposedMatrix;
}
// 这个示例将一个3x3矩阵顺时针旋转90度。输出是旋转后的矩阵，其中行的顺序已反转。
const matrix = [
[0, 0, 0, 0, 0],
[0, 1, 1, 1, 0],
[0, 0, 0, 0, 0],
];
const rotated = rotateMatrix(matrix);
console.log(rotated);
如果您遇到任何问题，请告诉我。
英文:
To transform a rectangular matrix by 90 degrees in JavaScript, you can use the following approach:
First, transpose the matrix by swapping its rows and columns. Then, reverse the order of the rows to obtain the 90-degree rotated matrix.
Here's an implementation of this approach and an example:
<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-js -->
//This function takes a rectangular matrix as its input and returns the rotated matrix
function rotateMatrix(matrix) {
const rows = matrix.length;
const cols = matrix[0].length;
// Transpose the matrix
const transposedMatrix = [];
for (let j = 0; j < cols; j++) {
const row = [];
for (let i = 0; i < rows; i++) {
row.push(matrix[i][j]);
}
transposedMatrix.push(row);
}
// Reverse the rows
for (let i = 0; i < cols; i++) {
transposedMatrix[i].reverse();
}
return transposedMatrix;
}
//This example rotates a 3x3 matrix by 90 degrees. The output is the rotated matrix, where the rows are in reverse order.
const matrix = [
[0,0,0,0,0],
[0,1,1,1,0],
[0,0,0,0,0],
];
const rotated = rotateMatrix(matrix);
console.log(rotated);
<!-- end snippet -->
Tell me if you are facing any problems.
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