creating a feature matrix

Hi, I have a cell array P of size 5000x1 which each element of it is another cell array of variable size (1xDIM). There is another cell array, vocab, of size 1x2000. The task is to create a matrix X of size 5000x2000 where X(i,j)=1 if vocab{1,j} is in P{i,1}. (P{i,1} is a cell array itself, not a single cell). I did this but the result is not correct:

for n=1:length(P)
    for m=1:length(vocab)
        if (strcmp(P{n},vocab{m}))
            X(n,m) = 1;
        else
            X(n,m) = 0;
        end
    end
end

Thanks,

Answer 1

[Jos (10584)]

I think this should work:

vocab = {'A','B','C','D'}    % 1-by-M cell array of strings
P = {{'A'} ; {'C','A'} ; {'B','A'}}    % N-by-1 cell array of cell array of strings
X = arrayfun(@(k) ismember(vocab, P{k,1}), 1:size(P,1), 'un', 0) ;
X = cat(1,X{:})    % a N-by-M logical array