Running environment: Python 3 environment of eclipse under MAC (Note: according to the original text, python 3.9 can also be solved in Python)

/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 20108 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 20803 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 39640 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 26031 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 20998 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 24067 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 65292 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 26679 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 26412 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 20010 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 25968 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:211: RuntimeWarning: Glyph 65306 missing from current font.
  font.set_text(s, 0.0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 39640 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 26031 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 20998 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 24067 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 65292 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 26679 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 26412 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 20010 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 25968 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 65306 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 20108 missing from current font.
  font.set_text(s, 0, flags=flags)
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/matplotlib/backends/backend_agg.py:180: RuntimeWarning: Glyph 20803 missing from current font.
  font.set_text(s, 0, flags=flags)

Warning reason: Matplotlib Chinese garbled code

Solution:

1. In the python environment of the terminal, view the font path (the terminal inputs the following command)

import matplotlib    
print(matplotlib.matplotlib_fname())

2. Download simhei

Go to the official download website and go to the specified directory: /library/frameworks/python.framework/versions/3.6/lib/python 3.6/site-packages/matplotlib/mpl-data/fonts/ttf, and move the downloaded simhei to this directory.

3. Delete the buffer directory of Matplotlib

In the python environment of the terminal, enter the following command to view the font cache path of Matplotlib:

import matplotlib
matplotlib.get_cachedir()

Then delete the cache using RM - RF + path

4. Modify the matplotlibrc file

Modify /library/frameworks/python.framework/versions/3.6/lib/python3.6/site-packages/matplotlib/mpl-data/matplotlibrc, as follows:

 font.family         : sans-serif   
 # Remove the leading#     
 font.sans-serif     : SimHei, Bitstream Vera Sans, Lucida Grande, Verdana, Geneva, Lucid, Arial, Helvetica, Avant Garde, sans-serif  
 # Remove the leading # and add SimHei after the colon
 axes.unicode_minus : False
 # Remove the leading # and change True to False

5. Restart eclipse