Need to read some values from a text file

I have a text file and I need to extract some values from the text file.

From line number 524 to 533, the Mode number and Eigen value need to be read and saved in a variable. Any help is appriciated.

Best Regard.

Answer 1

[Rik]

This process consists of multiple steps:

• read the file to a cellstr or to a string vector (you can use readlines on newer releases, and either regexp(fileread(___),'\n','split') or my readfile function, which you can get here)
• find where your data begins
• cut that section
• convert that to numbers

txt=readlines('https://www.mathworks.com/matlabcentral/answers/uploaded_files/824870/buck.txt');
txt=cellstr(txt);
start_ind=3+find(contains(txt,"MODE NO      EIGENVALUE"))

start_ind = 524

end_ind=find(cellfun('isempty',txt));end_ind(end_ind<=start_ind)=[];end_ind=end_ind(1)-1

end_ind = 533

txt(start_ind:end_ind)

ans = 10×1 cell array
    {'       1      5.28896E+06'}
    {'       2      5.28897E+06'}
    {'       3      5.29998E+06'}
    {'       4      5.30000E+06'}
    {'       5      5.31633E+06'}
    {'       6      5.31644E+06'}
    {'       7      5.33461E+06'}
    {'       8      5.33466E+06'}
    {'       9      5.36301E+06'}
    {'      10      5.36314E+06'}

Now you can use tools like split, textscan, etc to convert these to double, which I will leave as an exercise to you. Feel free to comment with your try if you have trouble implementing that.

[Rik]

About that legacy syntax for cellfun: that syntax is the only place where cellfun is faster than an ordinary loop, but you do have to be carefull.