Unable to "import matplotlib.pyplot as plt" in virtualenv

Question

I am working with flask in a virtual environment. I was able to install matplotlib with pip, and I can import matplotlib in a Python session. However, when I import it as

matplotlib.pyplot as plt 

I get the following error:

>>> import matplotlib.pyplot as plt  Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "//anaconda/envs/myenv/lib/python2.7/site-packages/matplotlib/pyplot.py", line 109, in <module>     _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()   File "//anaconda/envs/myenv/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup     globals(),locals(),[backend_name],0)   File "//anaconda/envs/myenv/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py", line 24, in <module>     from matplotlib.backends import _macosx RuntimeError: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends. 

I am confused about why it asks me to install Python as framework. Doesn't it already exists? What does it mean to "install Python as framework", and how do I install it?

Answer 1

This solution worked for me. If you already installed matplotlib using pip on your virtual environment, you can just type the following:

$ cd ~/.matplotlib $ nano matplotlibrc 

And then, write backend: TkAgg in there. If you need more information, just go to the solution link.

Answer 2

I got the same error, and tried Jonathan's answer:

You can fix this issue by using the backend Agg

Go to User/yourname/.matplotlib and open/create matplotlibrc and add the following line backend : Agg and it should work for you.

I run the program, no error, but also no plots, and I tried backend: Qt4Agg, it prints out that I haven't got PyQt4 installed.

Then I tried another backend: backend: TkAgg, it works!

So maybe we can try difference backends and some may work or install the requeired packages like PyQt4.

Here is a sample python snippet that you can try and test matplotlib.

import matplotlib  matplotlib.use('TkAgg') import matplotlib.pyplot as plt  plt.plot([1, 2, 3], [0, 3, 7]) plt.show()