Bulk concatenation of cell array contents (without looping)?

Hi,

I have a 1x4 cell whose elements are all 1x40 cells. Each of the elements of the 1x40 cells is a 1000x128 array of doubles.

Is there a way to concatenate the contents of the elements in the 1x40 cells into a 40000x128 array of doubles without looping through the elements individually?

Thanks, Alex

Answer 1

[Matt Fig]

There may be a way to do it with no loops, but I think this is fast anyway. Here is a full example. Just change the numbers according to your needs....

% Make a nested cell array, as you describe it. 
for ii = 1:4  % A 1-by-4 cell
    for jj = 1:3  % Each element is a 1-by-3 cell.
       BC{ii}{jj} = rand(2,5);  %#ok  And each has is a 2-by-5 double 
    end
end

%
%
%
%

% Now extract it.
A = zeros(2*3,5,4);

for ii = 1:4
    A(:,:,ii) = cat(1,BC{ii}{:});
end

A = reshape(permute(A,[1,3,2]),2*3*4,5);

[Danny Gonzalez]

This really helped out, thanks!

Answer 2

[Alex]

Ooops, I figured it out:

stackedarrays = vertcat(bigcell{1,1}{1,:})

If there is a better way, please let me know.

[Ali Ali]

Thanks a lot for your solution

Answer 3

[Ramis Rafay]

I think this will work for any given number of elements without looping

stackedarrays = vertcat(mycell{:,:})

[theblueeyeswhitedragon]

This gives you back a mxn matrix, which you could easily obtain by using cell2mat().