How to insert a column in a matrix of Matlab/Octave

To add a column in a matrix without replacing other existing columns in Matlab/Octave type [M V]

[M V]

• Parameter M is the name of matrix
• Parameter V is a column vector

This command outputs the array with a column added.

Examples

Example 1

Define a 3x3 matrix

>> M = [ 1 2 3 ; 4 5 6 ; 7 8 9 ]
M =
1 2 3
4 5 6
7 8 9

Define a column vector

>> V = [ 10; 11 ; 12 ]
V =
10
11
12

To append a column of the matrix type [M V]

[M V]

The command returns a 3x4 matrix with three rows and four columns

The vector is added as the last column of the matrix

ans =
1 2 3 10
4 5 6 11
7 8 9 12

Example 2

To insert a column as the first column of the matrix type [V M]

>> [V M]

The command returns a 3x4 matrix

The new column is added as the first column

ans =
10 1 2 3
11 4 5 6
12 7 8 9

Example 3

To add a column after the second column of the matrix, type [M(:,1:2) V M(:,3:end)]

>> [M(:,1:2) V M(:,3:end)]

The result is a 3x4 matrix

The command adds a new intermediate column to the matrix without replacing the other columns

ans =
1 2 10 3
4 5 11 6
7 8 12 9