how to make the length of culums equal

Hi i have code like this I want to scan my folder and for each wav in file( 5 files) i want to compute DFT the I want to fit them in a matrix F which will have 5 columns.

Of course i cannot do it because the size of each wav isnt the same so can you guys help me with this

I can make each wav of same time length and it would work

But what i want to do is for example if first file has 10 000 rows 1 columns and second file 7000 rows and 1 column i want to add 3000 rows of ones into the ceond file and so on for other 3 files.

Make them all equeal so i can find a mean of each row of the 5 files

for (i=1:length(D)) % for each wav file in the given path:
    curFileName = [classPath D(i).name];
    FileNamesTemp{i} = curFileName;
    % mid-term feature extraction for each wav file:
   [a] = audioread(curFileName);
  % signal = struct('Filt_data', data, 'SampleRate', fs);
  if (size(a,2)>1)
    a = (sum(a,2)/2);% convert to MONO
  end
   stFeatures = getDFT(a);
   % stFeatures = stFeatureExtraction(a, 44100, stWin, stStep);
  
%    midFeatures = featureExtractionFile(curFileName, ...
%    stWin, stStep, mtWin, mtStep, listOfStatistics);
    % long-term averaging:
  %  longFeatures = mean(stFeatures,2);       
    
   % F = [F longFeatures];
   
   F(:,i) = stFeatures;
end

Answer 1

[Walter Roberson]

numD = length(D);
F = zeros(0, length(D));

for i = 1 : numD
    
    stuff and then
    
    Frows = size(F,1);
    numFeat = length(stFeatures);
    if Frows < numFeat
        %new file is bigger than anything so far, extend all existing rows with 1
        F(Frows+1:numFeat, :) = 1;
    elseif numFeat < Frows
        %new file is smaller than what we have seen so far, extend it with 1
        stFeatures(numFeat+1:Frows) = 1;
    end
    F(:, i) = stFeatures;
end