Concatenate a variable number of matrices

Hi All,

How can I concatenate a variable number of matrices that is decided by the user's input?

Thanks..

[Stephen23]

This is simple. Ensure that you store all of the matrices in one cell array C, then you can simply do this:

cat(3,C{:})

You can change the dimension to suit your needs. Also you can easily select how many you want to concatenate, by using simple and efficient indexing 1:N:

cat(3,C{1:N})

Note that accessing lots of separate variables inside a loop is very slow, complex and buggy:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Answer 1

[KL]

I suppose your matrices have (in fact, they should be) consistent dimensions, so you could as well store them in ND array.

 dummy = rand(3,3,5);
 user_choice = 3; %concatenate first 3 matrices
 res = reshape(dummy(:,:,1:user_choice),size(dummy,1),size(dummy,2)*user_choice)

Is this what you want?