# how to append matrices of different sizes together

3 views (last 30 days)
jaah navi on 10 Mar 2020
Edited: Ameer Hamza on 10 Mar 2020
I am having three different matrices as
A = [1 2; 3 4]
B = [4 5 6; 7 8 9]
C=[10 11 12 13; 14 15 16 17]
i want to have the result in the following manner
D=[ 1 2;
3 4;
4 5 6;
7 8 9;
10 11 12 13;
14 15 16 17]

#### 1 Comment

Ajay Kumar on 10 Mar 2020
Does appending 0's or NaN's work?

Ameer Hamza on 10 Mar 2020
Edited: Ameer Hamza on 10 Mar 2020
In MATLAB, all the rows and columns of the matrix must be of equal length. If you just want to combine them in one variable, I suitable way is to use cell Array;
A = [1 2; 3 4]
B = [4 5 6; 7 8 9]
C= [10 11 12 13; 14 15 16 17]
D = {A,B,C}
The other option is to replace the absent entries with NaN
A = [1 2; 3 4];
B = [4 5 6; 7 8 9];
C = [10 11 12 13; 14 15 16 17];
D = {A,B,C};
mat_sizes = cellfun(@(x) size(x), D, 'UniformOutput', 0)';
max_dims = max(cell2mat(mat_sizes), [], 1);
result = cellfun(@(x,y) ...
D', mat_sizes, 'UniformOutput', 0);
result = cell2mat(result);