Extracting data from a cell array problem

Hi folks,

I have extracted data from an SQLite file into MATLAB, and have it saved as a (1000,4) cell array, wherein the contents of the 4th column are numbers (1, 2 or 3). I am trying to extract rows of data from this cell array on the basis of the contents of the 4th column (see code below), but MATLAB tells me that I cannot perform this particular operation on the contents of a cell.

results_solo                =   fetch(conn, sqlquery_soloEvents);

AnimalData                  =   'SELECT ID, RFID, GENOTYPE, NAME FROM ANIMAL';
results_animalData          =   fetch(conn , AnimalData);

% Create a structure containing our data

for k = 1:size(results_animalData)
    data(k).Mice            =   results_animalData(k,4);
    data(k).Genotype        =   results_animalData(k, 3);
    data(k).RFID            =   results_animalData(k,2);
    data(k).ID              =   cell2mat(results_animalData(k,1));
    data(k).Behaviours      =   results_solo(results_solo(:,4) == k, :);
end

Therefore, I rewrote the code using strcmpi to the following:

for k = 1:size(results_animalData)
    data(k).Mice            =   results_animalData(k,4);
    data(k).Genotype        =   results_animalData(k, 3);
    data(k).RFID            =   results_animalData(k,2);
    data(k).ID              =   cell2mat(results_animalData(k,1));
    data(k).Behaviours      =   results_solo(strcmpi(results_solo(:,4), k), :);
end

But this is not working either. So then I tried to directly access the contents of my cell as follows:

for k = 1:size(results_animalData)
    data(k).Mice            =   results_animalData(k,4);
    data(k).Genotype        =   results_animalData(k, 3);
    data(k).RFID            =   results_animalData(k,2);
    data(k).ID              =   cell2mat(results_animalData(k,1));
    data(k).Behaviours      =   results_solo(results_solo{:,4} == k, :);
end

But that is not working. (it gives an error saying that in the final line I have too many input arguments).

Can someone point me towards what I should do next?

[Tommy]

Try

data(k).Behaviours      =   results_solo(cellfun(@(c) c==k, results_solo(:,4)), :);

[Amy Hassett]

This also worked! Thank you!

Answer 1

[Ameer Hamza]

Try this

data(k).Behaviours      =   results_solo([results_solo{:,4}] == k, :);
                                        %^ add square brackets

[Amy Hassett]

This worked perfectly thank you!

[Ameer Hamza]

Glad to be of help.

[Stephen23]

How it works:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists