How to add specific values from column vectors (of multiple files) to a new vector?

Hi,

We would need help with the following problem.

We have 100 .mat- data files and each of those files contains 4 column vectors (each column vector has 50 values). With the help of people in this community we created a for-loop which reads the files, "addresses" specific columns within the files and performs simlpe calculations with the values of these columns (see commands below).

%   % Select multiple Out4 files and open them 
  cd (thePath.data)               
  [F,P]=uigetfile('*.*','MultiSelect', 'on'); 
  Re=zeros(length(F),1);
  for i = 1:length(F)
       data = load(F{i});
   varnames = fieldnames(data);
  firstvar = varnames{1};
  HR1 = data.(firstvar)(:,3);
      Re(i)= nanmean(HR1)
  end

What we now need to do is the following:

1. We created a vector consisting of zeros of a certain length:

      Z = zeros(100,1)

2. We want to extract a certain number of values from the 3rd column vecctor. The position and number of extracted values will differ from mat- data file to mat- data file.

3. The extracted values should be added to the vector Z starting at its 20th value. This is how we began with solving the problem:

Z(20:(20+MST)) = Z(20:(20+MST)) + HR1(mACToff:mACTon)

- mACToff is the first value to be extracted from the 3rd column (calculated in a previous step);

- mACTon is the last value from the 3rd column (calculated in a previous step);

- MST is mACTon - mACToff (defines the length of the extracted piece);

- HR1 is the name we assigned to the 3rd column vector (see the loop above).

4. The problem now is to add the extracted values from each .mat- data file to this one vector Z. Is it possible to do this with a nested loop or a loop or in any other way and what would the commands exactly look like?

Thank you for any suggestions!