要安装 matplotlib 库，建议使用此库：
python -m pip install -U pip
python -m pip install -U matplotlib
当我执行以下代码时：
(base) C:\WINDOWS\system32>python -m pip install -U pip
结果出现此警告：
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
Requirement already satisfied: pip in c:\programdata\anaconda3\lib\site-packages (22.0.4)
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
所以这样-U matplotlib做：
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
WARNING: Ignoring invalid distribution -atplotlib (c:\programdata\anaconda3\lib\site-packages)
Requirement already satisfied: …