MATLAB: How to find the nonzero values in an cells array?.

Question

The following code generates an cell array Index [1×29], where each cell is an array [29×6]:

for i = 1 : size(P1_cell,1)
    for j = 1 : size(P1_cell,2)
        [Lia,Lib] = ismember(P1_cell{i,j},PATTERNS_FOR_ERANOS_cell{1},'rows'); 
        Index1(i,j) = Lib  % 29x6
    end
        Index{i} = Index1; % 1x29
end

How can I find the nonzero values in an cells array?, and generate an array with the values from that search. I tried the following loop, but it doesn't work, it creates conflict with the previous one:

for i = 1 : length(Index)
            
    for j = 1 : length(Index)
        Non_ceros = length(find(Index{:,i}(j,:))); %%  I just need the length of the find function output
    end
end

I need help, Thanks in advance.

Answer 1

Non_ceros=zeros(length(Index));
for i = 1 : length(Index)      
    for j = 1 : length(Index)
        Non_ceros(i,j) = nnz(Index{i}(j,:));
    end
end