insert rows and columns in a matrix

Hello,

I have a 3x3 matrix and I want to make it 4x4 matrix by inserting a row and column of zero elements. How can I do that?

Thanks,

Rakesh

Answer 1

[Star Strider]

One approach:

M = rand(3);
Mz = zeros(size(M,1)+1, size(M,2)+1);
Mz(1:size(M,1), 1:size(M,2)) = M;

producing (here):

Mz =
      0.95717      0.14189      0.79221            0
      0.48538      0.42176      0.95949            0
      0.80028      0.91574      0.65574            0
            0            0            0            0

Experiment to get the result you want.

[Rakesh Belchandan]

Thanks for the answer though. But what I want to do is:

3x3 matrix should become 4x4 matrix

but new 4x4 matrix has zero rows and columns at the 3rd row and 3rd column. 4th row and column will be last row and column of 3x3 matrix with zeros in place.

[Rakesh Belchandan]

Oh great.. I can just chnage rows and columns in your solution. Thanks.

[Star Strider]

My pleasure.

That was not part of your original Question!

Just exchange the various rows and columns:

Mz([1 2 4 3],[1 2 4 3]) = Mz

producing for the original ‘Mz’:

Mz =
      0.34039      0.75127      0.69908            0
      0.58527       0.2551       0.8909            0
      0.22381      0.50596      0.95929            0
            0            0            0            0

and the ‘shuffled’ ‘Mz’:

Mz =
      0.34039      0.75127            0      0.69908
      0.58527       0.2551            0       0.8909
            0            0            0            0
      0.22381      0.50596            0      0.95929

Experiment to get the result you want.