Inserting matrices in a cell - in a for loop

I have to create eleven matrices with fiber photometry data coupled with occurrence of eleven stimuli, to understand how each of them affects neural activity. After that, I want to store them in a cell. This is the outcome that I'm aiming for:

In this case, there was no data to record for stimuli from 6 to 11, but that's ok.

After 90 lines of code, this is the part where I try to put data in those matrices. However, with the same exact file, what I get is:

Inside each of those cells:

So, a) it looks like data are shifted towards right b) instead of having matrices within a cell, I have matrices within cells within a cell.

This is the correct code:

dff1 = [];
dff2 = [];
dff3 = [];
dff4 = [];
dff5 = [];
dff6 = [];
dff7 = [];
dff8 = [];
dff9 = [];
dff10 = [];
dff11 = [];

for j = 1:length(num_ind)
        if num_ind(j)*Fs+epochlength > length(Activity)
            fprintf(' %d index is out of range of our read\n',j) ;
        else
        num_activity(:,j) = Activity_dff(num_ind(j)*Fs-epochlength:num_ind(j)*Fs+epochlength); 
        end
    end
    
    [r,c] = size(num_activity); 
    num_dff = num_activity;
    if code_events(i) == 1
        if length(dff1) ==0
         dff1=[dff1,num_dff];
        else
        dff1=[dff1;num_dff];
        end
    elseif code_events(i) == 2
        if length(dff2) ==0
         dff2=[dff2,num_dff];
        else
        dff2=[dff2;num_dff];
        end

And so on until eleven. Finally:

wholedff={dff1,dff2,dff3,dff4,dff5,dff6,dff7,dff8,dff9,dff10,dff11};
wholedff(1) = {dff1}

I tried to improve that code with this:

wholedff = cell(1, 11);

for c_event = 1:length(code_events)
    %Declare variable
    num_code = [];
    num_ind = [];
    num_activity = [];
    num_activity_mean = [];
    num_dff = [];
    if code_events(c_event) == 0 
    disp("Preventing unwanted parse");
    else
    num_code = find(a.events == code_events(c_event));
    num_ind = a.event_times(num_code);
    %Count number of events
    fprintf('Number of %d event is %d\n',code_events(c_event), length(num_code))
    
    %Getting the photometry points
    for j = 1:length(num_ind)
        if num_ind(j)*Sampling_rate+Epoch_length > length(Activity)
            fprintf('%d index is out of range of our read\n',j) ;
        else
        num_activity(:,j) = Activity_dff(num_ind(j)*Sampling_rate-Epoch_length:num_ind(j)*Sampling_rate+Epoch_length); %-20 seconds +20seconds of the event time   
        end
    end
    
    [~,c] = size(num_activity);
    num_dff = num_activity;
    
    if isempty(wholedff{c_event})
            wholedff{c_event} = [wholedff(c_event),num_dff];
        else
            wholedff{c_event} = [wholedff(c_event);num_dff];
    end
    end
end

dff1 = cell2mat(wholedff{1});
dff2 = cell2mat(wholedff{2});
dff3 = cell2mat(wholedff{3});
dff4 = cell2mat(wholedff{4});
dff5 = cell2mat(wholedff{5});
dff6 = cell2mat(wholedff{6});
dff7 = cell2mat(wholedff{7});
dff8 = cell2mat(wholedff{8});
dff9 = cell2mat(wholedff{9});
dff10 = cell2mat(wholedff{10});
dff11 = cell2mat(wholedff{11});

However, it's clearly not working

Answer 1

[Stephen23]

You need to get the data out of the cell array before concatenating it with the new data, i.e. replace

wholedff{c_event} = [wholedff(c_event),num_dff]

with

wholedff{c_event} = [wholedff{c_event},num_dff]
%                            ^       ^ correct indexing

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-cell-array.html