How to remove a matrix column in Matlab and Octave

To delete a column of a matrix in Matlab / Octave, type

M(:,n)=[ ]

• M is the name of the array (two-dimensional array)
• n is the number of the column to be deleted
• [] is an empty vector

Examples

Example 1

Define a 2x4 matrix

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

To delete the first column of the matrix, type M(:,1)=[ ]

>> M(:,1)=[]
M =
2 3 4
6 7 8

The first column is removed from the matrix

The result is a 2x3 matrix

Example 2

Define a 3x3 matrix

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

To remove the second column of the matrix type M(:,2)=[ ]

>> M(:,2)=[]
M =
1 3
4 6
7 9

This command deletes the second column of the matrix

The result is a 2x3 matrix.