Cell2mat - creating a matrix from mismatched cell sizes
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Karen Hornsby
on 16 Jan 2013
Answered: Samira Abedi
on 2 Jan 2019
Does anyone know how to create a matrix from a cell array where some of the cells have different lengths? Basically my instrument got interrupted when writing it's output file and finished halfway through a line. I don't want to discard the file as it's 99% complete. Is there another command which selectively converts a given sample size of a cell?
4 Comments
Matt J
on 17 Jan 2013
If your data is initially acquired as a file, how did it get into cell array form? Why would you import the file to a cell array if you ultimately want it to be a vector?
Samira Abedi
on 2 Jan 2019
I get the following error when applying the above code:
Attempt to grow array along ambiguous dimension.
Accepted Answer
Walter Roberson
on 17 Jan 2013
No, you cannot do that. So what you do instead is figure out where the smaller lines are and pad those rows with enough NaN to match the size of the other rows. Then you can cell2mat()
3 Comments
Walter Roberson
on 17 Jan 2013
prevlen = sum(cellfun(@length, C(end-1,:)));
lastlen = sum(cellfun(@length, C(end,:))));
C{end,end} = [C{end,end}, NaN(1,prevlen - lastlen)];
mat2cell(C)
Joel Torby
on 22 May 2018
C=yourCellArrayWithDifferentSizes;
maxLengthCell=max(cellfun('size',C,2)); %finding the longest vector in the cell array
for i=1:length(C)
for j=cellfun('size',C(i),2)+1:maxLengthCell
C{i}(j)=0; %zeropad the elements in each cell array with a length shorter than the maxlength
end
end
A=cell2mat(C); %A is your matrix
More Answers (2)
Jan
on 17 Jan 2013
What do you want as output for:
C = {[], 1, 1:2}
?
2 Comments
Jan
on 17 Jan 2013
No, "C" is a cell, which contains vectors of different length. Simply copy it to the command window and run it. It is exactly what you have explained by:
... a cell array where some of the cells have different lengths?
Now you ask us for creating a matrix from such an input. So how should the output look like in this case?
Samira Abedi
on 2 Jan 2019
I get the following error when I apply the suggested method:
Attempt to grow array along ambiguous dimension.
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