d=dir('yourmatchingFileWildCardExpression*.txt'); % get the list of candidate files dir() struct
pat=digitsPattern(1)+"."+digitsPattern(4,5); % define the numeric format looking for
N=numel(d);
data=zeros(N,2);
for i=1:N % iterate over the files
f=readlines(d(i).name); % read the file as string array
l=f(contains(f,"track-length keff = ")); % get the line of interest
data(i,:)=str2double(extract(l,pat)).'; % and extract the number values
end
NOTA BENE: The above assumes two fundamental things (not enough info supplied to verify either):
- The string "track-length keff = " is unique to the data line of interest in the file, and
- There is only one such line per file.
The above will require R2020b or later for both readlines and pattern.
