How to select next specific line based on string present in previous line and copy the line also from a text file?

x='$RAIM';
y='$GPGGA';
fid=fopen('myfile.txt');
while ~feof(fid)
  tline = fgetl(fid);
  if contains(tline,x)
      fprintf(id,'%s\n',tline)
end
end
fclose(fid)

% Input file contents

$RAIM,002212,003080,000818,001156,020000,020000,000777,001098,111,3,11111111*32
$GPGGA,151943.50,1257.32717,N,07738.23927,E,2,09,0.87,823.3,M,,M,,*44.

if second last column of RAIM line is 5 not 3 then only select GPGGA line otherwise go to next line.

Answer 1

[Walter Roberson]

S = fileread('myfile.txt');

gpgga_lines = regexp(S, '(?<=^\$RAIM,.*,5,[^,]*$)\$GPGGA,.*$', 'match', 'lineanchors', 'dotexceptnewline');

[POKA]

Hi, Thanks for response. If I execute your above code ,I can see only portion of GPGGA lines.I want to store both GPGGA and RAIM line in separate file if there is a match. From your code how to extract both GPGGA and RAIM lines.

[Walter Roberson]

S = fileread('myfile.txt');

chosen_lines = regexp(S, '^\$RAIM,.*,5,[^,]*\$GPGGA,.*$', 'match', 'lineanchors', 'dotexceptnewline');

[POKA]

Hi, How to store GPGGA and RAIM lines to external text file. Therefore number of RAIM and GPGGA lines would be same.From command I can not see the whole contents of GPGGA line. I am beginner of matlab

[POKA]

[Walter Roberson]

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

[POKA]

$RAIM,002212,003080,000818,001156,020000,020000,000777,001098,111,3,11111111*32 ..... $GPGGA,151943.50,1257.32717,N,07738.23927,E,2,09,0.87,823.3,M,,M,,*44 $RAIM,002205,003078,000814,001155,020000,020000,000778,001104,111,3,11111111*37 other lines $GPGGA,151943.75,1257.32721,N,07738.23936,E,2,09,0.87,823.5,M,,M,,*40 $RAIM,002205,003078,000814,001155,020000,020000,000777,001103,111,5,11111111*3F $GPGGA,151944.00,1257.32721,N,07738.23936,E,2,09,0.87,823.5,M,,M,,*45 ....so on

Ideal outputfile File1.txt $RAIM,002205,003078,000814,001155,020000,020000,000777,001103,111,5,11111111*3F File2.txt $GPGGA,151944.00,1257.32721,N,07738.23936,E,2,09,0.87,823.5,M,,M,,*45

[POKA]

It is very much helpful. What I missed earlier is that I not mentioned other lines between RAIM and GPGGA lines. Based on condition I want to store ALL RAIM lines in one file and GPGGA lines in another file. Thanks for your support . Thanks once again .

[POKA]

Very close to solution .I got correctly the file having GPPGA lines but also how to store those RAIM lines having 5 in another text file

[Walter Roberson]

Is it the case that you have RAIM lines that might have the special value in a particular field, and that following that you have other lines, and that when there is a match, you want to pull the GPGGA lines out, stopping at the next RAIM line?

If so then I would recommend using a loop of reading lines. That situation could probably be done by regexp but the expression would get kind of complex.

[POKA]

Yes, I have RAIM lines ,then in between other lines then GPGGA . Now if that particular filed of RAIM line is 5 then select that RAIM lines as well as next coming GPGGA lines and save then in two separate files for further processing. The loop shall continue till end of file. Through your code I got all GPGGA lines but not corresponding RAIM lines.

[POKA]

%How to write two if condition in matlab
% I want to try below logic while pulling out RAIM line having 5  in 67 position
x='$RAIM'
while ~feof(fid)
tline = fgetl(fid);
if contains(tline,x) && contains(tline,tline(:,67)==5)
fprintf(fid,'%s\n',tline)
fclose(fid)

[Walter Roberson]

p1 = '$RAIM'; p2 = '$GPGGA';
selecting_data = false;
while ~feof(fid)
  tline = fgetl(fid);
  if ~ischar(tline); break; end;   %end of file
  if strncmp(tline, p1, length(p1))
     selecting_data = tline(67) == '5';
     fprintf(fid, '%s\n', tline);
  elseif selecting_data && strncmp(tline, p2, length(p2))
     fprintf(fid, '%s\n', tline);
  end
end
fclose(fid);