Question

I have two matrices

a = randi ([0 10], 5, 6)
b = randi ([0 10], 2, 45)

Now I want to construct a matrix c of size 8 x 15 with all the elements of a and b. Is it possible to do it in a single line code? Some suggestions please.

Here is an example of what I’m trying to do:

a = [1 4 6;
     5 8 0;
     3 7 9;
     4 10 5];

b = [5 6;
     5 0];

c = [1 4 6 5;
     8 0 3 7;
     9 4 10 5;
     5 6 5 0]

Answer 1

The specifications for how to combine a and b aren’t clear. Here is one way to do it.

Create a single column vector built from a and b. Then reshape that column vector into a matrix.

c = reshape( [ a(:); b(:) ], 8, 15);

This will only work if the numel(a) + numel(b) equals the total number of elements in c.

Attempts to execute c = reshape( [ a(:); b(:) ], 7,12); will fail as you aren’t providing enough elements to create an 7x12 matrix.

Update
Noufal’s comment on this answer changes the problem reqs a bit. Basically you stil create the column vector but you only populate C depending on how many elements you have at your disposal:

A = rand(5,6);
B = rand(2,45);
C = zeros(8,10);

tmp = [A(:); B(:)]; % create temporary column vector

maxIdx = min( [numel(tmp), numel(C)] ); % determine if tmp or C has fewer elements

C(1:maxIdx) = tmp(1:maxIdx); % fill C from tmp using indices 1:maxIdx