Re: Reading tab-delimited ASCII files

[etienne]

  Hi all,

maybe you can strip your data from the first 2 columns, substitute the N/A for
NaN, save the result in a temp file and load that temp file?  As in the
following code (for unix system)

   ## Make data octave-readable
   system (["perl -w -p -e 's/.*?\t.*?\t//; s|N/A||ig' < ",your_file_name, "> 
/tmp/some_safe_temp_file_name.txt"]);

   ## Read it
   your_data = load ("/tmp/some_safe_temp_file_name.txt")

   ## let's be good and clean up
   unlink ("/tmp/some_safe_temp_file_name.txt")

(in production code, you'd want to use a temp name returned by tmpnam()).

  Hth,

  Etienne


On Tue, August 7, 2007 13:11, James Sherman Jr. wrote:
# Well, I can't attest to it being any faster, but something like
# [v1, v2, v3, v4] = fscanf(fid, "%s%s%s%s", 'Inf')
# Would give you an already parsed line with v1 being the first column in the
# line, and so on.  v[1-4] are still strings though, so doing some simple
# strcmp calls to check if the string is a N/A or an actually number to sort
# out the rest.
#
# Hope this helps.
#
# James Sherman
#
# On 8/7/07, Matthias Brennwald <address@hidden> wrote:
#>
#> Dear all
#>
#> I've got some ASCII file containing data which I'd like to read into
#> Octave. The ASCII files contain several lines and columns. The columns
#> are separated by tabs. The first column contains strings or variable
#> width (parameter names), the remaining columns contain mostly numbers
#> and some NaN values (e.g. 'N/A'). As an example, a file might look like
#> this:
#>
#> K_G     1E-2    N/A     0.1
#> KD_FIN  2       1.9     1.8
#> KD_COA  0.2     0.02    1.2E-2
#> T_LI    9.3244  8.233   N/A
#>
#> I tried using fscanf to read the data from the files, but I don't
#> understand how to use the template parameter to specify the data format.
#> I ended up reading line by line with fgetl and then analyzing each line
#> seperately. This works, but it's slow. I believe that the fscanf
#> function would be much faster. Can anyone give me an example of how to
#> efficiently read ASCII files, e.g. the one above?
#>
#> Matthias
#> _______________________________________________
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#>
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http://www.isr.ist.utl.pt/~etienne