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Hi all,

I am new to MATLAB, and I also asked previously something similar and got pretty good answer but I am not quite sure how to solve the issue which I didn't explain quite well. So, I have some 1010 matrices which have different row lengths but same number of columns. So I have matrices lets say 75x50, 73x50, 74x50, 85x50, 83x50, etc. But within each matrix, lets say the first one 75x50, columns have different lengths with numbers and then are filled with nan. Firstly, I want to crop them all into the smallest length of the column which contains only numbers and then in the other case extend all the matrices to the largest row length when filling with nan. I want to unfold matrices and concetrate them in a single matrix. Below the code crops the matrices at the smallest length of rows but not the smallest length of rows where all the columns contain only numbers and not nan.

Thank you in advance!

%% Initialize variables.

d='directory';

for i=1:1010

filename = [d sprintf('/name%05d/csvnames.csv', i)];

delimiter = ',';

startRow = 2;

%% Create output variable

frametable1final1 = cell2mat(raw);

H(i).matrix = frametable1final1(:,[2 3 13 14 15 16 17 18 19 20 24 36 48 49 50 58 59 60 72 73 74 75 76 88 89 90 91 99 263 316 317 318 320 344 357 870 910 927 928 929 948 949 950 969 970 971 975 976 977 981]);

end

minheight = min(arrayfun(@(s) size(s.matrix, 1), H)); %get height of each matrix and get minimum

trimmed = arrayfun(@(s) reshape(s.matrix(1:minheight, :), 1, []), H, 'UniformOutput', false); %trim and reshape matrices

X = vertcat(trimmed{:}); %vertically concatenate the lot

maxheight = max(arrayfun(@(s) size(s.matrix, 1), H)); %get height of each matrix and get maximum

padded = arrayfun(@(s) reshape([s.matrix; nan(maxheight - size(s.matrix, 1), size(s.matrix, 2))], 1, []), H, 'UniformOutput', false); %pad and reshape

Xprime = vertcat(padded{:});

Andrei Bobrov
on 20 Apr 2019

Edited: Andrei Bobrov
on 26 Apr 2019

M = struct2cell(H);

n = min(cellfun(@(x)find(all(~isnan(x),2),1,'last'),M));

M = cellfun(@(x)reshape(x(1:n,:)',1,[]),M,'un',0);

X = cat(1,M{:})

and (part 2 - fixed)

M = struct2cell(H);

[m,n] = cellfun(@size,M);

mm = max(m);

n = max(n);

for jj = 1:numel(H)

H(jj).matrix(isnan(H(jj).matrix)) = 0;

if m(jj) < mm

H(jj).matrix(mm,n) = 0;

end

end

Kelly Kearney
on 16 Apr 2019

Edited: Kelly Kearney
on 16 Apr 2019

Do any of your matrices have non-trailing blank/all-NaN lines that you want to preserve? Or are you just trying to strip out the NaN lines altogether?

If the former, you can do this pretty simply with a loop:

% Some example data

H(1).matrix = [...

1 2 3

NaN NaN NaN

4 5 6

NaN NaN NaN];

H(2).matrix = [...

7 8 9

10 11 12

13 14 15

16 17 18];

H(3).matrix = [19 20 21; nan(20,3)];

% Remove only trailing all-NaN rows

newh = cell(size(H));

for ii = 1:length(H)

[ridx,~] = find(~isnan(H(ii).matrix)); % identify row index of all numbers

newh{ii} = H(ii).matrix(1:max(ridx),:); % truncate matrix to max row with number

end

newh = cat(1, newh{:}) % concatenate

If you don't need to preserve any all-NaN rows, you can concatenate first and then just strip out the unwanted rows:

newh = cat(1, H.matrix); % concatenate

newh = newh(~all(isnan(newh),2),:) % remove all-NaN rows

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