Re: reading data using fgets in while loop

[indium]

On Sun, Mar 11, 2012 at 04:00:36PM -0700, newbie_octave wrote:
> I have a .csv file with the following data
> 
> 01/03/2012,H (Mar 12),26.750000,2584
> 01/04/2012,H (Mar 12),26.280000,2330
> 01/05/2012,H (Mar 12),26.000000,3198
> 01/06/2012,H (Mar 12),25.500000,3045
> 01/09/2012,H (Mar 12),25.350000,2314
> 01/10/2012,H (Mar 12),25.050000,2685
> 
> and I am a newbie to octave. I ran the following command to read the above
> data into octave
> 
> X=csvread("/tmp/hist.csv")
> 
> but it returns the following matrix.
> 
> 1.0000e+00   0.0000e+00   2.6750e+01   2.5840e+03
>    1.0000e+00   0.0000e+00   2.6280e+01   2.3300e+03
>    1.0000e+00   0.0000e+00   2.6000e+01   3.1980e+03
>    1.0000e+00   0.0000e+00   2.5500e+01   3.0450e+03
>    1.0000e+00   0.0000e+00   2.5350e+01   2.3140e+03
>   1.0000e+00   0.0000e+00   2.5050e+01   2.6850e+03
> 
> 
> Obviously, it is not reading the text correctly
> so I am now using fgets() as follows:
> 
> fid=fopen(fname);
> fout="out.mat"
> global tline;
> global tempstr;
> while 1
> tline = fgets(fid);
> sep=",";
> tempstr=strsplit(tline, sep);
> dt=tempstr(1);
> cname=tempstr(2);
> price=str2double(tempstr(3));
> volume=str2double(tempstr(4));
> if ~ischar(tline), break,end;
> end
> disp(tline);
> fclose(fid);
> 
> but when I run the script, it returns -1 due to disp(tline) being after the
> end. I want to be able to compute the volume-weighted average price, and not
> have to do it all within the script that reads the data from the file. But,
> given that I cannot access any of the variables outside the while loop, I am
> stuck. Ideally, I could have used csvread() or dlmread() but that is messing
> up the string fields in my file. Can anyone please suggest how I fix this so
> I can manipulate the variables outside the while loop that gets the data
> from the .csv file. thanks!
> 
> 
> 
> --
> View this message in context: 
> http://octave.1599824.n4.nabble.com/reading-data-using-fgets-in-while-loop-tp4464844p4464844.html
> Sent from the Octave - General mailing list archive at Nabble.com.

Hi, 
I would try while(!eof(fid)) instead of while(1). 
This would stop the while loop when the whole file is read. 

as an example, I've copied a part of a script that I use myself. This also does 
some date conversion to 'seconds since epoch'. 
To read the manual, do 'doc eof' or 'doc mktime', etc.

------------------------------------------------
params27C.date:
05/12/11 18:56:37 0.001728386 16.43405 1.323835
05/12/11 19:26:39 0.001676934 16.41423 1.334429
05/12/11 19:56:40 0.001599179 16.40604 1.351362
05/12/11 20:54:10 0.001547091 16.35170 1.361025
------------------------------------------------

script:

pos27f=fopen('./fits2012/27C/params27C.date');
n=0;
while (!feof(pos27f))
        n++
        line=strsplit(fgetl(pos27f),' ')
        datestring=sprintf('%s %s',line{1},line{2});
        pos27sec(n)=mktime(strptime(datestring,'%d/%m/%y %T'));
        pos27(n)=str2num(line{4});
endwhile
fclose(pos27f)