1，不知道為啥
py -3 -m pip install matplotlib
這樣安裝會報錯/缺少freetype和png組件/最后也沒解決問題/
解決方法：
https://www.lfd.uci.edu/~gohlke/pythonlibs/#pyside
找到Matplotlib, a 2D plotting library.
安裝matplotlib的必備組件：Requires numpy, dateutil, pytz, pyparsing, kiwisolver, cycler, setuptools, and optionally pillow, pycairo, tornado, wxpython, pyside, pyqt4, ghostscript, miktex, ffmpeg, mencoder, avconv, or imagemagick.
再下載相關的whl文件用pip安裝即可！