Manipulate numbers in existing txt file

Hi,

I want to manipulate numbers in a txt file which was created by catia. The txt file looks like this:

Catia puts a space between every string and float. For example I want to change 'l_overall (mm)' to 5000.

Thank you for your help!

[Walter Roberson]

I notice that there is a space between l_overall and (mm) and a space between w_overall and (mm) but no space between h_overall and (mm) . Is the actual file consistent about the space there or not?

Can we assume that the variables are always in exactly the same order and that we can assume that l_overall will be the first entry on the line (for example) ? Or is it necessary to match the strings to determine which column to make the change to ?

Is it possible that the fields are really tab delimited rather than space delimited ?

Answer 1

[Walter Roberson]

fid = fopen('Table1.txt', 'rt');
colnames = fgetl(fid);
colvals = fscanf(fid, '%f', [1 inf]);
fclose(fid)

colvals(1) = 5000;

fid = fopen('newTable1.txt', 'wt');
fprintf(fid, '%s\n', colnames);
fprintf(fid, '%g\t', colvals(1:end-1));
fprintf(fid, '%g\n', colvals(end));
fclose(fid)

[Stefan]

Thank you very much! I found my mistake.

Answer 2

[YT]

I don't know if I understand the question correctly, but if you want to change 'l_overall (mm)' to '5000' in your text file, you can do something like this (I assumed that your text file looks something like the test.txt I attached)

clear all;
fileID = fopen('test.txt');
C = textscan(fileID,'%s','delimiter','\n');
fclose(fileID);
C{:} = strrep(C{:},'l_overall (mm)','5000'); %replacing 'l_overall (mm)' by '5000'
writetable(cell2table(C{:}),'updated_data.txt','WriteVariableNames',0) %writing the new data

[Stefan]

Thank you for your help. The txt file Looks always like this and the variables are always in the exact same order. There is a space between every column header, unit and variable. I attached the file.

I tried a similar solution. The problem is 'textscan' and I get this error:

Error Using textscan Invalid file identifier. Use fopen to generate a valid identifier.

[Walter Roberson]

You would get that textscan error if you provided the wrong filename to fopen()

[Walter Roberson]

"There is a space between every column header, unit and variable"

The delimiter between columns is tab, just as I had guessed.