I need to put data from columns in different cells into one vector

Hi,

I have 1x20 cell and from each I need to take 4th column and put all of them in one long vector in order from 1-20. Moreover, these 4th vectors does not have same length. Is there any possibility for loop or any other easier solution than manually do it?

Thanks, Martin

Answer 1

[Robert U]

Hi Martin Pecha,

assuming your cells contain arrays of double:

 % Create input cell array
 cInput = cell(1,20);
 cInput = cellfun(@(cIn) rand(randi([4,10],1),randi([1,100],1)),cInput,'UniformOutput',false);

 % extract 4th column and concatenate vertically
 cOutput = cell2mat(cellfun(@(cIn) cIn(:,4),cInput,'UniformOutput',false)');

Kind regards,

Robert

Answer 2

[Pawel Jastrzebski]

Consider the following example:

% 1. Create fake data (you'll use the real data)

% create empty cell 1x20
c = cell(1,20)

% populate the cells 1 through 20 with a matrix
% that has 4 columns and random number of rows
for i=1:size(c,2)

      rcol = 4;
      rrow = randi([4 10]);

      c{i} = rand(rrow,rcol);    
  end

% 2. Extract 4th column out of every cell and
%    merge into vector

vector4 = [];

for i=1:size(c,2)

      % access data in i-th cell
      % and extract all values (:) from row 4
      GetCellData = c{i}(:,4);

      % append 'GetCellData' to an existing vector
      vector4 = [vector4; GetCellData];

end