Reading .txt files and replace lines from one file to another

Hello, I have a problem with a code.

First of all I have two .txt files, file1.txt and file2.txt. my problem is how to replace one line from one .txt with a line from another .txt file

I am uploading the two files in order to understand what I want to do. in these files, I would like to replace line 3 from File2 once with the first line of File1, once with the second line of file1 and once with the third line of File1.

I have to mention that i use readfile('File2.txt') in order to read this file.

Answer 1

[Walter Roberson]

lines1 = regexp(fileread('File1.txt'), '\r?\n', 'split');
lines2 = regexp(fileread('File2.txt'), '\r?\n', 'split');

replaced_lines = [lines2(1:2); lines1(2:4); lines2(3:end)];

fid = fopen('New_File2.txt', 'wt');
fprintf(fid, '%s\n', replaced_lines{:});
fclose(fid)

[Ivan Mich]

Hello, Thank you for your solution, but command window shows me :

Error using vertcat

Dimensions of arrays being concatenated are not consistent.

Error in test3 (line 8)

replaced_lines = [lines2(1:2); lines1(2:4); lines2(3:end)];

[Walter Roberson]

lines1 = regexp(fileread('File1.txt'), '\r?\n', 'split') .';
lines2 = regexp(fileread('File2.txt'), '\r?\n', 'split') .';

replaced_lines = [lines2(1:2); lines1(2:4); lines2(3:end)];

fid = fopen('New_File2.txt', 'wt');
fprintf(fid, '%s\n', replaced_lines{:});
fclose(fid)

[Ivan Mich]

Ok, one last question, if I would like to create a loop in order to create 3 different files ( I am uploading them in order to understand what I mean) what changes I should do? I mean could I use for command?

[Walter Roberson]

lines1 = regexp(fileread('File1.txt'), '\r?\n', 'split') .';
lines2 = regexp(fileread('File2.txt'), '\r?\n', 'split') .';

lines_to_replace_with = lines1(2:4);

for K = 1 : length(lines_to_replace_with)
   replaced_lines = [lines2(1:2); lines_to_replace_with(K); lines2(3:end)];
   newfilename = sprintf('New_File%d.txt', K+1);
   fid = fopen(newfilename, 'wt');
   fprintf(fid, '%s\n', replaced_lines{:});
   fclose(fid);
end

You would probably want to generalize this to figure out how many lines of input are in File1.

lines_to_replace_with = lines1(2:end);   %remove header
lines_to_replace_with(cellfun(@isempty, lines_to_replace_with)) = [];   %delete empty lines

I would also suggest to you that the desired output would be (for example):

there are several values
the problem is
6.4	100

without any repeated "there are several values" and so on.

[Ivan Mich]

Ok, in order to understand your suggestions I would like to ask something else. Lets suppose that I have one third file, "File3.txt". I am uploading it in order to understant it's format (This file has 7 columns and 4 lines-with Header). I would like to replace the third line of File2.txt with the 2nd and 3rd column of first line of File3.txt. I ve tried to make it but I can not clarify in matlab the spesific data I want.

The final .txt file I want is called "newfile.txt" (its uploaded too)

Could you help me please?

[Ivan Mich]

?

[Walter Roberson]

t3 = readtable('Files3.txt', 'readvariablenames', true);
nrow = size(t3,1);
lines2 = regexp(fileread('File2.txt'), '\r?\n', 'split') .';

for K = 1 : nrow
   line_to_replace_with = sprintf('%g\t%g',t3{K,2:3});
   replaced_lines = [lines2(1:2); line_to_replace_with; lines2(4:end)];
   newfilename = sprintf('newfile%d.txt', K);
   fid = fopen(newfilename, 'wt');
   fprintf(fid, '%s\n', replaced_lines{:});
   fclose(fid);
end

Your sample output file has a tab between the two values, so that is what I used.

I still have grave doubts that you really want the repeated "there are several problems" lines in your output files.

[Ivan Mich]

ok, well according to the above I have a problem to solve. Imagine that I have File3.txt, File2.txt and one .exe file (lets call it my.exe). File3.txt has my data, File2.txt is the input of my.exe(input that is needed in order to execute my.exe).

I would like from file3 to take only one line and put in a specific line of the file2(input). After putting this line in file2 I can run my exe file. The problem is that File 3 obtain many lines. I want to use o for loop in order to run my .exe file for all the lines separately of file3 (I mean I would like to take the first line of 2nd and 3rd column from file 3, put this line to file2, run my.exe file and take my results. After that I would like to take the second line of 2nd and 3rd column from file 3, put this line to file2, run my.exe file and take my results. After all this repeatability I would like to the last line of 2nd and 3rd column of file 3 put this line to file2, run my.exe file and take my results.)

I have to mention that I want after each repeatability the name of input file (File2.txt) does not change, inspite of the different content.

I wrote some commands but I realized that my work is not done.

%for 

% for j= 1: size{lines_to_replace_with,1}
% 
% line_to_replace_withnew = sprintf('%g\t%g',lines_to_replace_with(j));
% end 


t3 = readtable('Files3.txt', 'readvariablenames', true);
nrow = size(t3,1);
lines2 = regexp(fileread('File2.txt'), '\r?\n', 'split') .';

for K = 1 : nrow
   line_to_replace_with = sprintf('%g\t%g',t3{K,2:3});
   replaced_lines = [lines2(1:2); line_to_replace_with; lines2(4:end)];
   newfilename = sprintf('newfile%d.txt', K);
   fid = fopen(newfilename, 'wt');
   fprintf(fid, '%s\n', replaced_lines{:});
   fclose(fid);
end


system('my.exe <File2.txt')

Could you please help me?

[Ivan Mich]

?

[Walter Roberson]

It is 3 AM where I am. It is my bedtime now.

[Ivan Mich]

Sorry, the message I sent before 30 min (i mean the message "?") sent by my mistake..

of course answer whenever you want,

Thank you in advance

[Ivan Mich]

Excuse me, could anyone help me to solve my problem?

Thanking you in advance..

[Walter Roberson]

you have been shown all of tools you need. Splitting files into lines, selecting parts, replacing parts, creating output files from the modified versions.

When you system() out, you are always providing the same input file name in your i/o redirection. I do not know how you expect it to find the files you newly created. I think you need to construct the command that you pass to system()

[Ivan Mich]

I have written this code but I can not find the in order to run once for the first line of 2nd and 3rd column of File3 and execute the .exe, once for the second line of 2nd and 3rd columns and execute the .exe etc.

for i=1:size(t3,1)
    replaced_lines = [e(1:36);k;e(38:67);M(1:1);e(69:116);tr;ex(118:178);(t3(i,:)); e(180)]

    fid = fopen('file2.txt', 'wt');

    fprintf(fid, '%s\n', replaced_lines{:});

    fclose(fid)


system('my.exe<file2.txt')

end