MATLAB: How to add zeros column and row at the beginning of matrix

beginning of matrixzeros

I have A and B

A=[1,3,5;4,6,8;9,7,4]
B=[1,2,4,6;7,1,2,4;6,7,8,9;4,5,6,7]

if size(B)> size(A) Add zeros column and row at the beginning of matrix A

New_A=[0,0,0,0;0,1,3,5;0,4,6,8;0,9,7,4]

new_A=zeros(size(B));
new_A(2:end,2:end)=A;

Depends what you want in that column but you could for example add a column of zeros as follows:

A = [A zeros(size(A,1),1)]

I think the desired result could be the following.

     0     1     2     3     4     0     0
     0     0     5     6     7     8     0
     0     0     0     9    10    11    12

Assuming this, the solution would be like this.

A = [1,2,3,4; 5,6,7,8; 9,10,11,12];
A1 = [A,zeros(3)];
B = splitapply(@(x,d) circshift(x,d), A1, (1:3)', (1:3)');