 Open in App
Not now

# How to swap elements in the matrix in MATLAB?

• Last Updated : 24 Jan, 2022

In this article, we will see the swapping of elements into a matrix in MATLAB. Different methods are illustrated below:

## Method 1: By changing elements of rows and columns

In this method, we are simply changing the elements of particular rows and columns in the specified rows and columns respectively.

Example 1:

## Matlab

 `% MATLAB code for 2*2 matrix. its first and``% second elements of the first column are being swapped``A = [5  10``     ``15 20]``     ` `% Swapping the first and second elements of the first column``A([1 2]) = A([2 1])`

Output:

```A =
5   10
15   20
A =
15   10
5   20```

Example 2:

## Matlab

 `% MATLAB code for 3*3 matrix. The second and third elements of the first``% column are being swapped. And later, the first and second elements``% of the second column of the swapped matrix are swapped again.``A = [5  10 15``     ``20 25 30``     ``35 40 45]``     ` `% Swapping the second and third elements of the first column``A([2 3]) = A([3 2])` `% Swapping the first and second elements of the second column``% of the above swapped matrix``A([4 5]) = A([5 4])`

Output:

```A =
5   10   15
20   25   30
35   40   45
A =
5   10   15
35   25   30
20   40   45
A =
5   25   15
35   10   30
20   40   45```

## Method  2: By using randperm() and size() functions

In this approach, we are using the combination of randperm() and size() functions.

### randperm()

The randperm() function is used for the random permutation of integers of the specified matrix.

Syntax:

randperm(A)

Parameters: This function accepts a parameter.

• A: This is the specified matrix.

### size()

The size() function is used to return the size of each dimension of the specified array “X” or the size of the specified matrix “X”.

Syntax:

size(X)

[m,n] = size(X)

size(X,dim)

[d1,d2,d3,…,dn] = size(X)

Here,

size(X) returns the size of each dimension of the specified array “X” in a vector d with ndims(X) elements.

[m,n] = size(X) returns the size of the specified matrix “X” in the separate variables m and n.

size(X,dim) returns the size of the dimension of “X” specified by scalar dim.

[d1,d2,d3,…,dn] = size(X) returns the sizes of the first n dimensions of the specified array “X” in separate variables.

Parameters: This function accepts two parameters, which are illustrated below:

• X: It is the specified array or matrix or dimension.
• dim: It is the scalar value for the specified dimension “X”

Example 1:

## Matlab

 `% MATLAB code for swapping element``% of the array row-wise``% Initializing an array``A = [1 2 3``     ``4 5 6``     ``7 8 9];` `% Calling the randperm() function with``% size() as its parameter``random = A(randperm(size(A, 1)),:)`

Output:

```random =
7   8   9
1   2   3
4   5   6```

Example 2:

## Matlab

 `% MATLAB code for swapping elements``% of the array column-wise``% Initializing an array``A = [1 2 3``     ``4 5 6``     ``7 8 9];` `% Calling the randperm() function with``% size() as its parameter``random = A(:, randperm(size(A, 1)))`

Output:

```random =
3   1   2
6   4   5
9   7   8```

My Personal Notes arrow_drop_up