Question

I would like for the results generated with matchIdx to be saved to a matrix of separate vectors. This Idx can then be used as addresses in further manipulations.

The issue is when i try assigning to matchIdx(:,i) I get errors due to size mismatch of the columns.

I hope somebody can help out. Thank you.

data = [1;2;3;3;5;6;6;3;8;8;9;5;6;7;8;9;10];
check = [2;3;5];

for i=1:3
  match(:,i) = ismember(data,check(i));
  matchIdx = find(match(:,i))
end   

Answer 1

It’s not perfectly clear from your question, but I assume you tried

matchIdx(:,i) = find(match(:,i));

This is not going to work, since find(match(:,1)) and find(match(:,2)) are not guaranteed to be the same length.

Would using cell arrays work for you?

matchIdx{i} = find(match(:,i));