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[Grant Edwards]

In article <slrn89encl.mp4.jblaine at shell2.shore.net>, Jeff Blaine wrote:

>I had this very same need recently.  I got all excited about the Gnuplot
>module until I found out that it requires the Numeric C extension to Python.
>Was immediately disinterested, as I saw no reason for a pipe-based wrapper
>to require a C extension.
>
>I ended up doing the following
>
>        [ ... snip ... ]
>        # Create a data file here with the full path stored in 'tmpfilename'
>        gnuplot = os.popen('gnuplot', 'w')
>        gnuplot.write('set terminal gif\n')
>        gnuplot.write('set output "' + myfilename + '"\n')
>        gnuplot.write('set format "%.0f"\n')
>        gnuplot.write('plot "' + tmpfilename + '" with lines\n')
>        gnuplot.flush()
>        gnuplot.close()
>        [ ... snip ... ]

If you want, you can send the data down the pipe instead of
creating a tempfile. From the gnuplot help help on plot
special-filenames:

`'-'` is intended for situations where it is useful to have
data and commands together, e.g., when `gnuplot` is run as a
sub-process of some front-end application.  Some of the demos,
for example, might use this feature.  For example:

       plot '-','-'
       2
       4
       6
       e
       10
       12
       14
       e

>From the Python end, this would be something like:

  gnuplot.write('plot "-" with lines\n')
  gnuplot.write(dataString)   # data with a newline after each point
  gnuplot.write('e\n')

-- 
Grant Edwards                   grante             Yow!  I feel like a wet
                                  at               parking meter on Darvon!
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