macos - Python on Mac OS Pycharm gives framework error with "import matplotlib.pyplot as plt"

Question

This question is similar to the ones here and here but none of the solutions there work perhaps because I′m using a different environment (PyCharm on Mac OS).

In a virtual environment with PyCharm running on 2.7.15, matplotlib installed without any complaints, and a one-line PyCharm python file with the following content...

import matplotlib.pyplot as plt

...the console outputs the following error when running this one-line file:

/Users/jbs/PycharmProjects/WakeUp/env/bin/python /Users/jbs/PycharmProjects/WakeUp/InputSound/WakeInputSound-and-plot-it-trial3.py
Traceback (most recent call last):
  File "/Users/jbs/PycharmProjects/WakeUp/InputSound/WakeInputSound-and-plot-it-trial3.py", line 2, in <module>
    import matplotlib.pyplot as plt
  File "/Users/jbs/PycharmProjects/WakeUp/env/lib/python2.7/site-packages/matplotlib/pyplot.py", line 115, in <module>
_backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "/Users/jbs/PycharmProjects/WakeUp/env/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 62, in pylab_setup
[backend_name], 0)
  File "/Users/jbs/PycharmProjects/WakeUp/env/lib/python2.7/site-packages/matplotlib/backends/backend_macosx.py", line 17, 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. 

Any help resolving this would be most welcomed. I′ve tried about a dozen things and none seems to work...

(import matplotlib alone does not give problems and this question may be related to this one but it′s clearly different...)

Answer 1

For details refer: what-is-a-backend. You need to set your backend. There are two types of backends: user interface backends (for use in pygtk, wxpython, tkinter, qt4, or macosx; also referred to as “interactive backends”) and hardcopy backends to make image files (PNG, SVG, PDF, PS; also referred to as “non-interactive backends”).

There are four ways to configure your backend. If they conflict each other, the method mentioned last in the following list will be used, e.g. calling use() will override the setting in your matplotlibrc.

1. The backend parameter in your matplotlibrc file (see Customizing matplotlib):

   backend : WXAgg   # use wxpython with antigrain (agg) rendering
   

2. Setting the MPLBACKEND environment variable, either for your current shell or for a single script:

   > export MPLBACKEND="module://my_backend"
   > python simple_plot.py
   
   > MPLBACKEND="module://my_backend" python simple_plot.py
   

   Setting this environment variable will override the backend parameter in any matplotlibrc, even if there is a matplotlibrc in your current working directory. Therefore setting MPLBACKEND globally, e.g. in your .bashrc or .profile, is discouraged as it might lead to counter-intuitive behavior.

3. To set the backend for a single script, you can alternatively use the -d command line argument:

   > python script.py -dbackend
   

   This method is deprecated as the -d argument might conflict with scripts which parse command line arguments (see issue #1986). You should use MPLBACKEND instead.

4. If your script depends on a specific backend you can use the use() function:

   import matplotlib
   matplotlib.use('PS')   # generate postscript output by default
   

   If you use the use() function, this must be done before importing matplotlib.pyplot. Calling use() after pyplot has been imported will have no effect. Using use() will require changes in your code if users want to use a different backend. Therefore, you should avoid explicitly calling use() unless absolutely necessary.

Note:Backend name specifications are not case-sensitive; e.g., ‘GTKAgg’ and ‘gtkagg’ are equivalent.