Covert a cell to multidimensional matrix
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I have a 50 X 1 cell array, A, and each cell contains an m x 100 matrix, where m is variable and not the same for each of the cells. I would like to convert this cell array to a 3D matrix, Anew(M,100,50), where M is the first dimension of the matrix with biggest rows, and pad zero for the small matrices. I tried cell2mat but it concatenated the cell into a 2D matrix ([...],100). I also tried:
for ii=1:50
Anew(:,:,ii)=A{ii};
end
but I got
Subscripted assignment dimension mismatch.
error. Does anyone know how it can be done?
Thanks
This is the first 6 cells of A:
A =
[ 44x100 double]
[ 80x100 double]
[103x100 double]
[ 96x100 double]
[ 94x100 double]
[ 92x100 double]
.
.
.
0 Comments
Accepted Answer
Azzi Abdelmalek
on 12 Mar 2016
%------------Example---------------------------
s=arrayfun(@(x) randi(5,randi(5),100),1:5,'un',0)
%---------------the code-------------------------
n=max(cellfun(@(x) size(x,1),s))
m=size(s{1},2)
a=cellfun(@(x) [zeros(n-size(x,1),m);x],s,'un',0)
out=cat(3,a)
3 Comments
Guillaume
on 14 Mar 2016
Azzi made a mistake in the last line, it should be
out = cat(3, a{:});
Please use good variable names in your code, not m, n, a, etc. It makes the code so much easier to maintain:
%input cell array: c
maxheight = max(cellfun(@(m) size(m, 1), c);
resizedmatrices = cellfun(@(m) [m; zeros(maxheight - size(m, 1), size(m, 2)], c, 'UniformOutput', false);
out = cat(3, resizedmatrices{:});
More Answers (1)
Image Analyst
on 12 Mar 2016
Try this (untested) intuitive looping method:
Anew = zeros(m, 100, 50); % Initialize
for thisCellIndex = 1 : 50
% Extract contents of this particular cell.
% It will be a 1 x 100 row vector.
thismx100Array = A{thisCellIndex};
finalZ = min([size(Anew, 3), length(thismx100Array )]);
% Put this row vector into a column vector along the "Z" dimension.
for z = 1 : finalZ
Anew(1:m, 1:100, ii) = thismx100Array(z);
end
end
It's hard to do much more without your actual data.
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