How can I make each cell array consistent in length?

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Zara Khan
Zara Khan on 7 Mar 2019
Commented: Zara Khan on 19 Mar 2019
In a cell array each element is 1Xlength. This length is not equal. I want to get the maximum length and then want to make each cell with same length by padding zeros in it.

Accepted Answer

Jos (10584)
Jos (10584) on 18 Mar 2019
A final attempt to answer this question :-)
C = {1:4 1:2 ; 1:5 1:6 ; 1 1:3} % a m-by-n cell array
N = cellfun(@numel, C) % old lengths of cell elements
M = 3 ; % new length should be multiple of M
newN = M * ceil(N / M) % new lengths of cell elements
padfun = @(k) [C{k} zeros(1, newN(k) - N(k))] ;
C2 = arrayfun(padfun, 1:numel(C) , 'un', 0) ; % apply padding to all elements of C
C2 = reshape(C2, size(C)) % reshape (if needed)
  5 Comments

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More Answers (3)

tmarske
tmarske on 7 Mar 2019
Edited: tmarske on 7 Mar 2019
%set up a dummy example
tst = {[1 1], [1 1 1 1 1], [1 1 1], [1]}
%get the maximum length
maxlen = max(cellfun(@length, tst))
%pad zeros
tstPadded = cellfun(@(x)([x zeros(1, maxlen - length(x))]), tst, 'UniformOutput', false)
  13 Comments
Jos (10584)
Jos (10584) on 18 Mar 2019
Your question reads otherwise ... " I want to get the maximum length and then want to make each cell with same length by padding zeros in it.

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Jos (10584)
Jos (10584) on 7 Mar 2019
Edited: Jos (10584) on 8 Mar 2019
If you make them the same length, you can also store them in a matrix. In that case, my PADCAT function is your friend :-)
C = {[1 2] ; 1 ; [1 2 3]}
[M, tf] = padcat(C{:}) % pads with NaNs
M(~tf) = 0
PADCAT can be found on the File Exchange, for free:
(edited answer)
  6 Comments
Zara Khan
Zara Khan on 18 Mar 2019
Jos (10584):
by using padcat I am getting a matrix where all coloumns are merged. That I dont want. I want to keep each cell as it is, just want want to add extra zeros. Like , first cell is 1X16, second is 1X31 and so on. I want to work on each indivisually. By adding extra zeros the first cell will be suppose 1X32 and so on. Remember I am dealing with mXn cell array.

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Jos (10584)
Jos (10584) on 18 Mar 2019
C = {1:3 4 ; 5:9 10:12 ; 13:14 15} % a m-by-n cell array
N = cellfun(@numel, C)
maxN = max(N(:))
padfun = @(v) [v zeros(1, maxN - numel(v))] ;
C2 = cellfun(padfun, C , 'un', 0)
  3 Comments
Zara Khan
Zara Khan on 18 Mar 2019
A=cell(numImages,8);
B{k,j}=profile;
A=B;
len = cellfun(@length, B);
len1 = 32 * ceil(len/32);
width_needed=cell(numImages,8);
width_needed=len1-len;
I am making each cell a multiple of 32. Now my task is to pad extra zero after the multiplication. And I want to keep them as cell format , no merging will be done. Here the profile is varying in length. Basically it consists of consequtives 0's and 1's. I am attaching few pictures here too.

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