Use fprintf with fgetl

Hi, I have a text file. I use the fgetl to read all the lines from a text file (screenshot). filename is the path where is the text file. Where i find lines with abb_sat ("PE02") in the begginning of the line, I want to substitue the values in the original file with x_sp3, y_sp3, z_sp3 and dc_sp3 (fprintf inside the while). With this script I can sobstitue these values (x_sp3, y_sp3, z_sp3, dc_sp3) in the next lines and not in that one where I find "PE02". How can I use fprintf to sobsitute these values in the correct lines?

abb_sat = "PE02";

filename = strcat('C:\multiGNSS_v3\mgnssPre\ephConv\',out_sp3_abb,'\',num2str(YR+2000),'\',out_sp3_abb,num2str(WN),num2str(DoW),est);

FID = fopen ( filename , 'r+');

line = fgetl(FID);

x_sp3 = -10000.666666;

y_sp3 = -10.666666;

z_sp3 = -1000.666666;

dc_sp3 = -0.666666;

while ischar(line)

if ~isempty(strfind(line, abb_sat ))

fprintf(FID,'%.5s %13.6f %13.6f %13.6f %13.6f\n', abb_sat, x_sp3, y_sp3, z_sp3, dc_sp3);

end

line = fgetl(FID);

end

fclose(FID);

Answer 1

[VINAYAK LUHA]

Hi Francesco,

My understanding is that you have a text file with some lines beginning with "PE02" and you want a workaround to modify this line in the original file using "fprintf" function.

There are two issues in the code you shared-

1. The modified line appears after the line intended to be modified.
2. This makes the next line read using "fgetl" function non char array and the script unexpectedly terminates.

Here's a workaround that involves writing into a temporary file first and substituting the content with the original file at the end.

abb_sat = "PE02";
filename = strcat('C:\multiGNSS_v3\mgnssPre\ephConv\', out_sp3_abb, '\', num2str(YR+2000), '\', out_sp3_abb, num2str(WN), num2str(DoW), est);
tempFilename = 'temp.txt';

FID = fopen(filename, 'r');
FID_temp = fopen(tempFilename, 'w');
line = fgetl(FID);

x_sp3 = -10000.666666;
y_sp3 = -10.666666;
z_sp3 = -1000.666666;
dc_sp3 = -0.666666;

while ischar(line)
    if ~isempty(strfind(line, abb_sat))
        fprintf(FID_temp, '%.5s %13.6f %13.6f %13.6f %13.6f\n', abb_sat, x_sp3, y_sp3, z_sp3, dc_sp3);
    else
        fprintf(FID_temp, '%s\n', line);
    end
    line = fgetl(FID);
end
fclose(FID);
fclose(FID_temp);
fclose('all');
movefile(tempFilename, filename);

Hope this helps !

Regards

Vinayak Luha