# For loop with different length

60 views (last 30 days)
Uerm on 24 Nov 2019
Commented: Uerm on 25 Nov 2019
Hello,
I have a 1x10 cell (Var), where each cell is a 50*20000*A 3D array. I am trying to run the following code:
for k = 1:N
for j = 1:50
for i = 1:10
test{i} = mean(Var{i}(j,:,k));
test2{i} = std(Var{i}(j,:,k));
end
end
end
However, as apparent the number N will be different as A changes for each cell. How can I compute this with different N?

Roofus Milton on 25 Nov 2019
See last section of code. I used a counter variable which is incremented.
rows = 50;
columns = 20000;
randRange = [10, 50];
% create the cell array
data = cell(1, 10);
% loop over cell array and create matricies with varying size of third
% dimension
for p = 1:length(data)
data{p} = rand(rows, columns, randi(randRange));
end
% get the size of each matrix
dimensions = cell2mat(cellfun(@size, data, 'UniformOutput', false)');
% calculate how many rows will be needed
totalRows = sum(dimensions(:, 1) .* dimensions(:, 3));
% preallocate the output matrix
output = zeros(totalRows, columns);
% initialize the counter variable
counter = 1;
% loop over cell
for i = 1:length(data)
% loop over rows
for j = 1:dimensions(i, 1)
% loop over third dimension
for k = 1:dimensions(i, 3)
% assign the data
output(counter, :) = data{i}(j, :, k);
% increment the counter
counter = counter + 1;
end
end
end
Uerm on 25 Nov 2019
Sorry, my bad. I have edited the original question. Thanks a lot, I will try the code to see if it works.

R2019b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!