How do I force Matplotlib to draw while in the ipdb debugger in Spyder (or any other debugger)?

问题

EDIT

Unfortunately, at the moment this is not possible. I found out that it is a bug in Spyder. The developers are still figuring out how to approach this.

Goal

Visualize data while debugging code (and I want to use Spyder too!).

Attempt #1: Run foo.bar from IPython from Spyder

Create a file named foo.py with the following code:

from ipdb import set_trace as st
import matplotlib.pyplot as plt

def bar():
    st()

While in IPython, type the following:

In [4]: import foo

In [5]: foo.bar()
--Return--
None
> somewhere_over_the_rainbow\foo.py(5)bar()
      3 
      4 def bar():
----> 5     st()

ipdb> plt.plot([1, 2], [3, 4])
[<matplotlib.lines.Line2D object at 0x05CA8E90>]
ipdb> plt.show()

Plot remains in "frozen" state. If I exit debugger, plot updates. If I try to close the plot, IPython crashes. Obviously both undesirable, and neither lets me see the data while debugging.

Attempt #2: Run foo.bar from IPython from command line

Use same foo.py as in Attempt #1:

Open IPython from commandline:

In [4]: import foo

In [5]: foo.bar()
--Return--
None
> somewhere_over_the_rainbow\foo.py(5)bar()
      3
      4 def bar():
----> 5     st()

ipdb> plt.plot([1, 2], [3, 4])
[<matplotlib.lines.Line2D object at 0x03904070>]
ipdb> plt.show()

Program shows plot as I expect. BUT I want to use Spyder.

Attempt #3: Run baz.bar from IPython from command line

Write baz.py:

from ipdb import set_trace as st
import matplotlib.pyplot as plt

st()

Open IPython from commandline:

In [4]: import baz
--Return--
None
> somewhere_over_the_rainbow\baz.py(4)<module>()
      2 import matplotlib.pyplot as plt
      3 
----> 4 st()

ipdb> plt.

Then Spyder fully freezes.

Any suggestions?

Note #1: In my full code, I have many files and many functions, so mashing it all together in one script without functions is not viable.

Note #2: Using any matplotlib interactive command (e.g. ion(), interactive(True), etc.) had no effect.

Note #3: Spyder version 2.0.12, Python 2.6, matplotlib 1.0.1.

回答1:

(Spyder dev here) Note: Sorry for answering this one after so much time, but perhaps someone else will find it uself.

The best solution right now (November/13) is to use the pause(n) command from matplotlib (where n is a number of seconds) after showing the plot on pdb. Here is an example:

from matplotlib.pyplot import imshow, pause
import numpy as np
x = np.random.rand(4,5)
imshow(x)
pause(1)

Check out this comment from Jed Ludlow, one of our former devs, where he describes this solution.

回答2:

Have you considered the ion() function when importing pylab? This should allow interactive plotting in pdb.

 import pylab
 import pdb
 pylab.ion()

 tst_xdata = [1,2,3,4,5,6]
 tst_ydata = [1,1,1,1,1,1]

 pylab.plot(tst_xdata,tst_ydata)
 pylab.draw()

 pdb.set_trace()
 for idx in range(3):

     tst_ydata = [elem+2 for elem in tst_ydata]
     pylab.plot(tst_xdata,tst_ydata)
     pylab.draw()

 pylab.show()

The above works on my machine (Ubuntu 11.04, Python 2.7, SciPy bersion 0.8.0), even running in Eclipse with PyDev.