MATLAB: How to extract specific data from data files

dataextractfileMATLABread

There are multiple data files and I attached two as examples. For each of the data file, there are two data blocks. I want to extract the line corresponding to F=1.0000 in each data block, and combine the two lines into one. Then create a new file which includes the extracted data for all the data files.
For file "test1", the two lines corresponding to F=1.0000 are
  • 1.0000 0.98581 -23.906 5.74804 164.322
  • 1.0000 0.0674 0.84738 9.741 0.2434
The extracted data would be
  • 1.0000 0.98581 -23.906 5.74804 164.322 0.0674 0.84738 9.741 0.2434
Similarly, the extracted data for file "test2" would be
  • 1.0000 0.98373 -23.184 5.52288 164.574 0.0690 0.84402 12.860 0.2598
The new file I want to obtain will include the extracted data from "test1" and "test2"
  • 1.0000 0.98581 -23.906 5.74804 164.322 0.0674 0.84738 9.741 0.2434
  • 1.0000 0.98373 -23.184 5.52288 164.574 0.0690 0.84402 12.860 0.2598
What's a good way to realize this? Thank you.

Best Answer

I'm fairly certain there is a better way of doing this, but I personally would scan through each document with a for loop, and then use fgetl to extract the specific lines.
for nf = 1:length(files); % Loop through all files
 count = 0; % Reset line counter
 line = 1; % Reset line value
 a = 1;
 file = fopen(files(nf)); % Open new file
 while line ~= -1; % Run to end of file
  line = fgetl(file); % Read next line
  if length(line)<5; % Ignore small lines
  elseif strcmp(line(1:6)),'1.0000')==1; % Look for lines beginning with desire value
   datahold(a,:) = num2str(line); % You may have issues with this line converting correctly, but this should give
                                  % the concept of what you want to accomplish
   a = a+1; % Add new line to array for new data to recover
  end % Line value check
  count = count+1; % Advance line count
 end % while loop
 extracted(nf,:) = [datahold(1,:) datahold(2,2:end)]; % Only accounts for two lines extracted, transforms to one line
end % File loop
It's far from perfect, but it should get you started.
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