RE: reading data using fgets in while loop

[financial engineer]

> Date: Mon, 12 Mar 2012 10:17:32 -0700
> From: address@hidden
> To: address@hidden
> Subject: Re: reading data using fgets in while loop
>
>
> 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!
> >
> > I also get the following error in using strsplit, and I don't understand
> > what mistake I am making as I am following the usage guidelines. I tried
> > split, but I am advised to use strsplit.
> > octave-3.2.4:110> strsplit(tline,sep)
> > error: Invalid call to strsplit. Correct usage is:
> >
> > -- Function File: [S] = strsplit (P, SEP, STRIP_EMPTY)
> >
> >
> > Additional help for built-in functions and operators is
> > available in the on-line version of the manual. Use the command
> > `doc <topic>' to search the manual index.
> >
> > Help and information about Octave is also available on the WWW
> > at http://www.octave.org and via the address@hidden
> > mailing list.
> >
>
> There are a few more text reading functions that may help out.
> E.g., textread:
> (applied to your data in a file txt.csv)
>
> octave-3.6.1.exe:2> [a, b, c, d] = textread ('tst.csv', "%s %s %f %d",
> "delimiter", ",")
> a =
> {
> [1,1] = 01/03/2012
> [2,1] = 01/04/2012
> [3,1] = 01/05/2012
> [4,1] = 01/06/2012
> [5,1] = 01/09/2012
> [6,1] = 01/10/2012
> }
> b =
> {
> [1,1] = H (Mar 12)
> [2,1] = H (Mar 12)
> [3,1] = H (Mar 12)
> [4,1] = H (Mar 12)
> [5,1] = H (Mar 12)
> [6,1] = H (Mar 12)
> }
> c =
>
> 26.750
> 26.280
> 26.000
> 25.500
> 25.350
> 25.050
>
> d =
>
> 2584
> 2330
> 3198
> 3045
> 2314
> 2685
>
> With some postprocessing (e.g., datenum (a, "dd/mm/yyyy") ) you can get any
> output you want.
>
> Philip
>
>
> --
> View this message in context: http://octave.1599824.n4.nabble.com/reading-data-using-fgets-in-while-loop-tp4464844p4466694.html
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thanks Philip,
...I realize that I don't have textread.m in my io folder. can you tell me where can I download it.
Bobby