Connecting to gnuplot with Popen?

[Anton81]

Hi,

it seems to be a FAQ, but I still haven't found a solution. I want to
control gnuplot with a python program. The following at least gives me the
gnuplot output:

subp=Popen("gnuplot",stdin=None,stderr=PIPE,stdout =PIPE)
....
subp.stderr.readline()

even though I'm not sure how to check if no more lines can be read with
readline() so that it doesn't block.
But after the script has finished, the console doesn't show me the
characters I type.

However, as soon as I try:

subp=Popen("gnuplot",stdin=PIPE,stderr=PIPE,stdout =PIPE)
....
subp.stderr.readline()

the program hangs.

What's wrong?

Anton

[Dan Sommers]

On Thu, 30 Mar 2006 12:59:01 +0200,
Anton81 <fo***@anton.e4ward.com> wrote:

it seems to be a FAQ, but I still haven't found a solution. I want to
control gnuplot with a python program ...

Unfortunately, I don't know how to solve your problem, but try this:

http://gnuplot-py.sourceforge.net/

Regards,
Dan

--
Dan Sommers
<http://www.tombstonezero.net/dan/>
"I wish people would die in alphabetical order." -- My wife, the genealogist

[Markus Weihs]

> I want to control gnuplot with a python program.

Hi Anton,

here is a little snippet using os.popen:
import os

gp = os.popen('gnuplot -persist', 'w')
print >> gp, "set yrange [-300:300]"
for n in range(300):
print >> gp, "plot %i*cos(x)+%i*log(x+10)" % (n,150-n)
Regards, mawe

[Anton81]

> Hi Anton,

here is a little snippet using os.popen:

Unfortunately I'm having more problem getting the output from Gnuplot, which
I'd like to examine for error messages and settings of options.

Anton

[Laurent Pointal]

Anton81 a écrit :

Hi,

it seems to be a FAQ, but I still haven't found a solution. I want to
control gnuplot with a python program. The following at least gives me the
gnuplot output:

Unless you absolutely need to write your own code, you should try:
http://gnuplot-py.sourceforge.net/

A+

Laurent.

[John J. Lee]

Anton81 <fo***@anton.e4ward.com> writes:

Hi Anton,

here is a little snippet using os.popen:

Unfortunately I'm having more problem getting the output from Gnuplot, which
I'd like to examine for error messages and settings of options.

If you must roll your own, look at standard module subprocess.
John