why matplotlib give the error [<matplotlib.lines.Line2D object at 0x0392A9D0>]?

Question

I am using python 2.7.9 on win8. When I tried to plot using matplotlib, the following error showed up:

from pylab import *
plot([1,2,3,4])

[matplotlib.lines.Line2D object at 0x0392A9D0]

I tried the test code "python simple_plot.py --verbose-helpful", and the following warning showed up:

$HOME=C:\Users\XX matplotlib data path C:\Python27\lib\site-packages\matplotlib\mpl-data

You have the following UNSUPPORTED LaTeX preamble customizations:

Please do not ask for support with these customizations active.

loaded rc file C:\Python27\lib\site-packages\matplotlib\mpl-data\matplotlibrc matplotlib version 1.4.3 verbose.level helpful interactive is False platform is win32 CACHEDIR=C:\Users\XX.matplotlib Using fontManager instance from C:\Users\XX.matplotlib\fontList.cache backend TkAgg version 8.5 findfont: Matching :family=sans-serif:style=normal:variant=normal:weight=normal:stretch=normal:size=medium to Bitstream Vera Sans (u'C:\Python27\lib\site-packages\matplotlib\mpl-data\fonts\ttf\Vera.ttf') with score of 0.000000

What does this mean? How could I get matplotlib working?

rayryeng rayryeng · Accepted Answer · 2015-09-25T03:57:32

That isn't an error. That has created a plot object but you need to show the window. That's done using pyplot.show()... so you seriously just have to do...

show()

If you don't believe me, here's a trace from IPython:

In [9]: from pylab import *

In [10]: plot([1,2,3,4])
Out[10]: [<matplotlib.lines.Line2D at 0x123245290>]

In [11]: show()

We get:

As mentioned in the comments, you should avoid using pylab. You should use matplotlib.pyplot instead.... so:

import matplotlib.pyplot as plt
plt.plot([1,2,3,4])
plt.show()

why matplotlib give the error [<matplotlib.lines.Line2D object at 0x0392A9D0>]?

7 Answers