using findstr function for scanning strings in text file.

2.11           OBSERVATION DATA    M (MIXED)           RINEX VERSION / TYPE
teqc  2014Jan16     NOAA/NOS/NGS/CORS   20150102 00:26:47UTCPGM / RUN BY / DATE
Solaris x86 5.10|AMD64|cc SC5.8 -xarch=amd64|=+|=+          COMMENT
teqc  2014Jan16     NOAA/NOS/NGS/CORS   20150102 00:15:53UTCCOMMENT
BIT 2 OF LLI FLAGS DATA COLLECTED UNDER A/S CONDITION       COMMENT
BRMU                                                        MARKER NAME
42501S004                                                   MARKER NUMBER
Giovanni Sella      NGS                                     OBSERVER / AGENCY
351248              LEICA GRX1200GGPRO  8.71/3.823          REC # / TYPE / VERS
00480               JAVRINGANT_DM   NONE                    ANT # / TYPE
2304703.4760 -4874817.1770  3395186.9500                  APPROX POSITION XYZ
      0.0000        0.0000        0.0000                  ANTENNA: DELTA H/E/N
   1     1                                                WAVELENGTH FACT L1/2
  10    L1    L2    L5    C1    C2    P2    C5    S1    S2# / TYPES OF OBSERV
        S5                                                # / TYPES OF OBSERV
  30.0000                                                 INTERVAL

%Above is the rinex.txt file. I need to classify how many # / TYPES OF OBSERV string exist. The below code works proper in text file if only 1 line includes # / TYPES OF OBSERV.

fide = fopen('rinex.txt')
head_lines = 0
while 1 
     head_lines = head_lines+1
     line = fgetl(fide)
      answer = findstr(line,'# / TYPES OF OBSERV')
       if ~isempty(answer) 
           break;  
       end
end

%The second # / TYPES OF OBSERV doesn't appear in line.

Answer 1

[Guillaume]

Of course, your code only finds the 1st occurence of the string. You've designed it this way:

• read one line at a time ( fgetl(fide))
• find the occurrences of the string in the line ( strfind(line,...)
• if an occurrence found stop reading ( if ... break;)

If you want to find all the occurrences in the whole file, then read the whole file at once:

filecontent = fileread('rinex.txt');
noccurrences = numel(strfind(filecontent, '# / TYPES OF OBSERV'));

[sermet]

I need to stop the loop when there is no any other # / TYPES OF OBSERV then I can see the lines which involve all # / TYPES OF OBSERV

[Guillaume]

Ok, I misunderstood. You have two options:

1) using strfind, don't break out of the loop when you've found your string. Do whatever you need to do and carry on with the loop. Only break out of the loop when you encounter the end of file

fide = fopen('rinex.txt')
while true
   line = fgetl(fide)
    if ~ischar(tline) %eof
       break;
    end 
    if ~isempty(strfind(line,'# / TYPES OF OBSERV'))
       %do whatever you need to do with the line and carry on
    end
end

2) read the whole file and use a regular expression to extract the lines of interest

filecontent = fileread('rinex.txt');
observations = regexp(filecontent, '^.*(?=# / TYPES OF OBSERV\s*)$', 'match', 'lineanchors', 'dotexceptnewline');

the above regular expression will return the content of each line that ends with '# / TYPES OF OBSERV'

edit: added 'dotexceptnewline' to regex and match for blank spaces

[sermet]

hi,

The second codes produces observations =

     {}

the first one just read the entire file and gives

line =

    -1

[Guillaume]

Don't accept an answer until you're satisfied with the solution.

The second codes produces observations = {}

I'd forgotten that matlab's regexp engine by default matches newlines with dot which is the complete opposite behaviour of any other regex engine I know (C++, .Net, php, python, java, ruby, perl ...). Therefore the regular expression needs a 'dotexceptnewline' option.

Secondly, the regex assumes that 'TYPES OF OBSERV' terminates the line with no space afterward. Maybe you have spaces afterward.

I've edited my answer to fix the above two. In any case, you may need to tailor the regular expression to the exact pattern you have.

The first one just read the entire file and gives line = -1

Of course it would, you need to replace the comment %do whatever you need... with whatever code you need to process the line. (store it in a cell array? parse it?)