Easiest would be to read the file line-by-line, looking for the magic value and then save data until the next, adding the trial as a variable...
You forgot to attach any usable data for anybody to actually demonstrate, but "air code" would look something like --
fid=fopen('YourFile.Dat');
ID=input('Enter the magic ID to look for, please; ','s')
ID=upper(ID);
pat="MSG"+wildcardPattern+digitsPattern(7)+wildcardPattern+"TRIALID"+wildcardPattern+digitsPattern(1,4)+wildcardPattern+upper(ID);
j=0; % the counter
d=[]; % empty accumulator for data
l=fgetl(fid);
while ~feof(fid)
if matches(l,pat)
j=j+1; % increment counter
l=fgetl(fid); % get first data line in section
end
try
d=[d;[j str2double(l)]]; % convert line to data; add trial number and array
l=fgetl(fid); % record for next loop
catch % presume failure means next section
% do nothing special, pass on to next test if in wanted section
l=fgetl(fid); % record for next loop
end
end
fid=fclose(fid);
will (hopefully) leave you with the array of values with the trial # as first variable; save as a matrix or convert to a table as desired.
