Reshape array of cells with different column sizes into matrix

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Ardo Laaneots
Ardo Laaneots 2017-12-7
回答： Jos (10584) 2017-12-7
Hi. I need to reshape a T1 = [1x5] cell array, where each cell is a [5x1] cell array of numbers into a S1 = [m-by-n] matrix of numbers. The problem is the initial cell array T1 may have different number of rows in each cell - meaning I don't have a square shaped array to use " cell2mat " function.
Example:
T1=[1x5] cell array
T1{1} T1{2} T1{3} T1{4} T1{5}
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24
I need to add all of the columns together:
T2=
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24
And then reshape the array into [m-by-n] array (always square shaped), in this example S1=[3x8]:
S1=
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
I thought that maybe I could reshape T1 into [x-by-1] array and then reshape that array in to S1=[m-by-n]. But what should i do in order to get results like this:
T3=
1
2
3
4
...
24
And not like
1
6
11
16
21
2
...
24
Any help would be appreciated.

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采纳的回答

Jos (10584)
Jos (10584) 2017-12-7
Here is a way:
T = {[1:5:21]',[2:5:22]',[3:5:23]',[4:5:24]',[5:5:20]'}
m=3
n=8
[M, tf] = padcat(T{:})
M = M.'
out = reshape(M(tf.'),n,m).' % swap m and n, and then transpose
PADCAT concatenates unequal sized vectors by padding shorter ones with NaNs. This function can be downloaded from the File Exchange: https://uk.mathworks.com/matlabcentral/fileexchange/22909-padcat-varargin-

更多回答（1 个）

KL
KL 2017-12-7
One approach is to make all elements equal in size by padding 0s or nans and then use cell2mat,
m = max(cellfun(@numel,T1));
for k = 1:numel(T1)
n = numel(T1{k});
if n<m
T1{k} = [T1{k}; nan(m-n,1)];
end
end
T2 = cell2mat(T1)'

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