Modify a text file

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Izem
Izem on 3 Sep 2020
Commented: Izem on 9 Sep 2020
Hello everyone,
I have a .dat file like in the picture and I would like to modify I3 values (the last column). I can't use textscan since the beginning of the file has a different format.
Do you have any idea on how can I do this ?
  3 Comments
Izem
Izem on 3 Sep 2020
Thank you sir for your answer !
I am using Matlab 2019b. Yeah I want to keep everything exactely the same except the last column where I want to replace the values by (old values+Delta(m,n)) .
How can I get the char array ?
Izem
Izem on 3 Sep 2020
Sorry for my stupid question. I am new to Matlab.
I think you mean :
C = fileread('text.dat');
Then I can modify those values. Thanks again.

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Accepted Answer

Rik
Rik on 3 Sep 2020
You can get my readfile function from the FEX or through the AddOn-manager (R2017a or later).
data=readfile(filename);
HeaderLines=9;
delta=rand(numel(data)-HeaderLines,1);%generate some random data for this example
for n=(HeaderLines+1):numel(data)
%store in temp variable
str=data{n};
%read the value, add something to it, and merge back
ind=strfind(str,' ');ind=ind(end)+1;%assumes you don't have a trailing space and the delimiter is a space
lastval=str2double(str(ind:end));
lastval=lastval+delta(n-HeaderLines);
str=sprintf('%s%.3f',str(1:(ind-1)),lastval);
%store back to array
data{n}=str;
end
%write back to file (overwrites the original)
fid=fopen(filename,'wt');
fprintf(fid,'%s\n',data{:});
fclose(fid)
  17 Comments
Rik
Rik on 9 Sep 2020
I would separate finding the value of the correction and using it. I also would not use i and j as variables. You might also consider using ismember and/or find. A possible optimization would be to convert the mcorrection and ncorrection arrays to double only once (so outside the loop).
So no, I don't see any 'bad programming' here.
Izem
Izem on 9 Sep 2020
Alright! thank you sir for your help, I do appreciate it !

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