在 JavaScript 中转置二维 (2D) 数组

给定一个二维数组（矩阵），任务是使用 JavaScript 获得矩阵的转置。

方法一：

• 将二维数组存储到变量中。
• 显示二维数组（矩阵）内容。
• 调用 map() 方法，该方法为数组中的每个元素提供一个回调函数，保持顺序，并从结果中返回一个新数组（原始数组的转置）。

示例：此示例使用array.map()方法来获取数组的转置。

HTML

    
        
            Transpose of a 2D array
        
    
 
    
     
        
            GeeksForGeeks
        
     
            
        
 
         
        
            Click here
        
         
        
        
 
         
        
            var el_up = document.getElementById("GFG_UP");
            var el_down = document.getElementById("GFG_DOWN");
             
            var array = [
                            [1, 1, 1],
                            [2, 2, 2],
                            [3, 3, 3],
                        ];
             
            el_up.innerHTML = "[ [ " + array[0] + " ] ], [ [ "
                             + array[1] + " ] ], [ [ " + array[2] + " ] ]";
             
            function transpose(mat) {
                for (var i = 0; i < mat.length; i++) {
                    for (var j = 0; j < i; j++) {
                        const tmp = mat[i][j];
                        mat[i][j] = mat[j][i];
                        mat[j][i] = tmp;
                    }
                }
            }
             
            function gfg_Run() {
                array = array[0].map((col, i) => array.map(row => row[i]));
                 
                el_down.innerHTML = "[ [ " + array[0] + " ] ], [ [ "
                        + array[1] + " ] ], [ [ " + array[2] + " ] ]";
            }        
        
    

输出：

• 在点击按钮之前：
  

• 点击按钮后：
  

方法二：

• 将二维数组存储到变量中。
• 用相对于数组对角线的镜像替换数组中的每个元素。

示例：此示例创建一个函数，该函数将每个元素替换为其镜像以获取数组的转置。

HTML

    
        
            Transposing a 2D array
        
    
     
    
         
        
            GeeksForGeeks
        
         
            
        
 
         
        
            Click here
        
         
        
        
 
         
        
            var el_up = document.getElementById("GFG_UP");
            var el_down = document.getElementById("GFG_DOWN");
             
            var array = [
                            [1, 1, 1],
                            [2, 2, 2],
                            [3, 3, 3],
                        ];
             
            el_up.innerHTML = "[ [ " + array[0] + " ] ], [ [ "
                    + array[1] + " ] ], [ [ " + array[2] + " ] ]";
             
            function transpose(mat) {
                for (var i = 0; i < mat.length; i++) {
                    for (var j = 0; j < i; j++) {
                        const tmp = mat[i][j];
                        mat[i][j] = mat[j][i];
                        mat[j][i] = tmp;
                    }
                }
            }
             
            function gfg_Run() {
                transpose(array);
                el_down.innerHTML = "[ [ " + array[0] + " ] ], [ [ "
                        + array[1] + " ] ], [ [ " + array[2] + " ] ]";
            }        
        
    
                   

输出：

• 在点击按钮之前：
  

• 点击按钮后：