JavaScript: Returns n rows by n columns identity matrix

JavaScript Function: Exercise-10 with Solution

Write a JavaScript function which returns the n rows by n columns identity matrix.

Pictorial Presentation:

Sample Solution-1:

JavaScript Code:

function matrix(n) {

        var i;
        var j;

        for (i=0; i < n; i++)
        {
          for (j=0; j < n; j++)
          {
               if (i === j)
               {
                
                 console.log(' 1 ');
               }
                      
               else 
                {
                 console.log(' 0 ');}
                }
             console.log('----------');
           }
       }
matrix(4);

Sample Output:

 1 
 0 
 0 
 0 
----------
 0 
 1 
 0 
 0 
----------
 0 
 0 
 1 
 0 
----------
 0 
 0 
 0 
 1 
----------

Flowchart:

Live Demo:

See the Pen JavaScript -Returns n rows by n columns identity matrix-function-ex- 10 by w3resource (@w3resource) on CodePen.

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Sample Solution-2:

JavaScript Code:

function identity_matrix(n) {
  let imatrix = [];
  for (let i = 0; i < n; i++) {
    let row = [];
    for (let j = 0; j < n; j++) {
      if (i === j){
        row.push(1);
      } else {
        row.push(0);
      }
    }
    imatrix.push(row);
  }
  return imatrix;
}
console.log(identity_matrix(4));

Sample Output:

 [[1,0,0,0],[0,1,0,0],[0,0,1,0],[0,0,0,1]]

Explanation:
The above function first creates an empty matrix array “imatrix“ to hold the identity matrix. It then loops through n times to create n rows and columns. In each row, the array is created empty, and then the loop is repeated n times to create each column. For each column, it checks if the row index i is equal to the column index j. If i and j are equal, it pushes a 1 to the row array, otherwise it pushes a 0. After completing the row, it pushes the row array to the matrix array. Upon creating all rows and columns, the function returns the matrix array representing the identity matrix.

Flowchart:

Live Demo:

See the Pen javascript-function-exercise-10-1 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus

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