Matlab - vectorized way to indices in cell array equal string

Question

I have a 435x1 cell array whose elements are either 'y', 'n', or '?'. I want to find which indices are equal to 'y'.

With normal arrays, I just use the find function. But I can't use that with cell arrays because eq is not defined for type cell.

I think I can go through each element and do

for index=1:size(cell_array,1)
    if cell_array{index} == 'y'
        %add index to some array of indices
    end
end

But is there a vectorized way to go through the array and find indices contain elements that are equal to 'y'? Any help is appreciated.

possible duplicate of How to search for a string in cell array in MATLAB? — Eitan T
– Eitan T, Commented Oct 29, 2013 at 7:00
@EitanT - I think Sterling was most interested in the [cell_array{:}]=='y' bit, which was not a possible solution for the other question, so find could be used in the familiar way with eq. It's much the same functionally, I'll admit. — chappjc
– chappjc, Commented Oct 29, 2013 at 7:11

chappjc · Accepted Answer · 2013-10-29 04:32:21Z

5

Since you know each cell will contain a single character you can concatenate all the cell elements and do a single vectorized test:

find([cell_array{:}]=='y')

Possibly the most straightforward way is just to use strcmp, which can accept a cell array as the second argument:

find(strcmp('y',cell_array))

answered Oct 29, 2013 at 3:31

chappjc

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3 Comments

More precisely, you'd want find(strcmp('y',cell_array)), so that you'd get the indices of the 'y' values.

Thanks, I'll clarify that you need find around strcmp.

+1 The second method is more general, as it doesn't require single-chracter strings