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kill python listener which opened matplotlib figure [closed]

asked 2013-04-16 23:36:59 -0600

Hunk gravatar image

updated 2014-01-28 17:16:13 -0600

ngrennan gravatar image


i wrote a visualization with matplotlib in python.

import matplotlib.pyplot as plt

def callback(data):
do something

def listener():
rospy.Subscriber('topic', data, callback)

 Main function.
if __name__ == '__main__':
# Initialize the node and name it.

   rospy.init_node('pylistener', anonymous = True)
   # Go to the main loop.

i want to print my figure. The problem is when he get a message he stop till i close the figure. That is fine. But when i want to close the program with ctrl+c the program crash and i have to close the terminal.

It is possible to kill the node and the python program after i close the figure?

Or what i can do against this crashing? It is really annoying that i have to close the terminal and restart it.

thank you for your help and sry i am new on python

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Closed for the following reason the question is answered, right answer was accepted by SL Remy
close date 2016-09-08 12:34:06.584438


Also, where do you define data?

SL Remy gravatar image SL Remy  ( 2013-04-19 10:01:32 -0600 )edit

1 Answer

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answered 2013-04-17 02:30:39 -0600

SL Remy gravatar image

updated 2013-04-17 10:10:40 -0600

My guess is that you're sending more than just one data packet, thus attempting plot more than once. That's the reason why it hangs.

ps -ef in another terminal will show you the PID for the program and a kill PID should stop the process.

In any case, to get past the core issue, I'd suggest using savefig saving files with a unique name, appending timestamp is one approach, and the you can print at your leisure. You should use clf after you save the figure though.

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yes i send more then one message. It is not possible to kill the node and the python program after i received the first one and I closed the figure?

Hunk gravatar image Hunk  ( 2013-04-17 03:00:08 -0600 )edit

if you kill the node then the data that you're also killing the subscriber to the data that trying to plot.

SL Remy gravatar image SL Remy  ( 2013-04-17 04:36:53 -0600 )edit

My suggestion is to use savefig/clf instead of using show(), since that method "block[s] until the figures have been closed"

SL Remy gravatar image SL Remy  ( 2013-04-17 04:45:19 -0600 )edit

I only want to see one plot. So it doesn't matter if my plot get more data. When i save my figure i get every time i receive the message a new identical file.

Hunk gravatar image Hunk  ( 2013-04-18 23:20:42 -0600 )edit

Is the published data actually changing? (rostopic echo -p /yourtopic)...

SL Remy gravatar image SL Remy  ( 2013-04-19 09:57:40 -0600 )edit

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Asked: 2013-04-16 23:36:59 -0600

Seen: 1,751 times

Last updated: Apr 17 '13