Question

In a matrix, to remove the columns in which the element of the first line is 0, we can use:

ind2remove = (A(1,:) == 0);
A(:,ind2remove) = [];

How do I do that if A is a cell? I want to remove the columns in which the element of the first row is 0.

I tried:

ind2remove = (A{1,:} == 0);
A{:,ind2remove} = [];

but I got the error message:

??? Error using ==> eq
Too many input arguments.

Error in ==> ind2remove = (A{1,:} == 0);

Answer 1

Indexing using { } gives you the contents of the cell, whereas indexing using ( ) returns the same type as the original object i.e., if A is a cell, A{i,j} will return what it’s holding, and A(i,j) will always return a cell. You need the latter.

So in your case, you can do the following to eliminate all columns where the first row has a 0.

A(:, cellfun(@(x)x==0, A(1,:))) = [];

The assumption here is that each cell in the first row holds only a single numeric element, as per your comment.