How to edit a particular row of a particular column of .dat file ?
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I am currently working with a code which requires me edit a particular value in a column corresponding to a particular row. Following is an example of
my_dat
Some information about the file
3 !number of months
Jan 45 36 0.05
Feb 55 23 0.0016
Nov 12 7 0.45
I want to change the value 0.0016 in the last column for Feb to say 0.23. I have tried using 'textread' but only reads the first line. I also want matlab to keep the filetype after editing the file.
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Answers (2)
Azzi Abdelmalek
on 31 Jul 2016
Edited: Azzi Abdelmalek
on 31 Jul 2016
fid=fopen('filename.dat')
d=textscan(fid,'%s %f %f %f')
fclose(fid)
M=cell2mat(d(:,2:4))
%Or
[a,b,c,d]=textread('fic.dat',' %s %f %f %f')
3 Comments
Walter Roberson
on 31 Jul 2016
Are you sure you used cell2mat(d(:,2:4)) instead of accidentally using cell2mat(d) ?
Walter Roberson
on 31 Jul 2016
fid = fopen('my_dat.dat', 'r');
lines{1} = fgetl(fid);
lines{2} = fgetl(fid);
lines{3} = fgetl(fid);
datacell = textscan(fid, '%s%f%f%f');
fclose(fid);
month_names = datacell{1};
month_col1 = datacell{2};
month_col2 = datacell{3};
month_col3 = datacell{4};
month_col3(2) = 0.23;
And then after that you write the data out to a new file.
There is no way to edit a text file "in place", with the exception of the uncommon case where what you are writing out is exactly the same size as what is already in the file, such as if you wrote 0.2300 to match the size of 0.0016 . Writing text files "in place" is tricky.
There are some other approaches that can be used for the case where you know the exact string you need to substitute for.
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