# Randomly Shuffle Rows in MATLAB Matrix

MATLAB is a great tool to process matrices. It provides a large number built-in functions and processing methods that we can use to manipulate our matrices just by writing a small piece of MATLAB codes. Such an operation that we can perform on matrices in MATLAB is random shuffling of rows of a matrix. In this tutorial, I will explain how you can randomly shuffle rows of a matrix using MATLAB.

## Randomly Shuffle Rows of a Matrix in MATLAB

MATLAB is a complete solution to manipulate matrices using computers. In MATLAB, we can very easily shuffle rows of a matrix by using MATLAB's built-in functions.

MATLAB has a built-in function namely, 'randperm' that we can use to shuffle or swap the rows of a given matrix randomly. This function shuffles the rows of the matrix by generating a random permutation of indices of rows. This randomly generated permutation allows us to rearrange the rows of our matrix in a random order.

Before going to discuss the practical implementation of the concept, let us first discuss the step-by-step process of shuffling of rows of a matrix in MATLAB.

## Process of Randomly Shuffling Rows of a Matrix using MATLAB

The step-by-step procedure to shuffle the rows of a matrix randomly using MATLAB programming is explained below:

Step (1) – First of all, create or load the matrix that you want to manipulate in the MATLAB workspace.

Step (2) – Determine the number of rows in the matrix. For this you can use a MATLAB's built-in function 'size'. The following syntax of the 'size' function is used to determine the number of rows in a matrix:

Rows_Num = size(matrix, 1);


Here, '1' is used to specify that we want to determine first dimension (row) of the matrix.

Step (3) – Now, use the 'randperm' function to generate a random permutation of indices of matrix rows. For this, the following syntax is to be used:

Rand_Perm = randperm(Row_Num);


Step (4) – In this step, utilize the randomly generated permutation to reorder/shuffle the rows of the matrix.

Step (5) – Finally, display the result.

We now have the enough knowledge to implement the MATLAB code to perform random shuffling of rows of a matrix.

### Example

Let us take an example program to understand how actually we can write the codes in MATLAB to shuffle the rows of a given matrix.

% MATLAB code to shuffle rows of a matrix randomly
% Create a sample matrix
Mat = [10, 20, 2; 42, 51, 67; 57, 85, 19; 1, 15, 2];

% Determine the number of rows in the matrix
n = size(Mat, 1);	% dim = 1 to specify rows

% Generate a random permutation of indices of rows of the matrix
R = randperm(n);

% Shuffle the rows of the matrix using random permutation
Shuffled_Mat = Mat(R, :);

% Display the input and shuffled matrices
disp('The input matrix is:');
disp(Mat);
disp('The shuffled matrix is:');
disp(Shuffled_Mat);


### Output

The input matrix is:
10   20    2
42   51   67
57   85   19
1   15    2
The shuffled matrix is:
10   20    2
1   15    2
42   51   67
57   85   19


### Explanation

In this MATLAB code, we shuffled the rows of the input matrix using the randomly generated permutation.

## Conclusion

This is all about random shuffling of rows of a matrix using MATAB. In this tutorial, we explained the step-by-step process to shuffle the rows of a matrix with the help of an example.

In conclusion, MATLAB has a built-in function 'randperm' that can be used to randomly shuffle the rows of a matrix by utilizing the randomly generated permutation of row indices of the matrix.

Updated on: 07-Sep-2023

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