解决 Mac PyCharm 无法用 matplotlib 作图的报错

报错信息如下

#...
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.

解决办法，在终端中

$ cd ~/.matplotlib
$ vim matplotlibrc

编辑文件输入

backend: TkAgg

保存推出，再进去 PyCharm 既可以使用 matplotlib 作图。