安装 Polygon 报错需要依赖 Microsoft Visual C++ 14.0

Question

使用 pip 安装 Polygon 报错，需要 Microsoft Visual C++ 14 或者是 Microsoft Visual C++ Build Tools 构建工具：

Building wheels for collected packages: Polygon3
  Building wheel for Polygon3 (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: 'C:\Users\dell\anaconda3\envs\tfenv\python.exe' -u -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\dell\\AppData\\Local\\Temp\\pip-install-mznbfad2\\polygon3_cee40c7ea0c6484b9af12f81b433d085\\setup.py'"'"'; __file__='"'"'C:\\Users\\dell\\AppData\\Local\\Temp\\pip-install-mznbfad2\\polygon3_cee40c7ea0c6484b9af12f81b433d085\\setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d 'C:\Users\dell\AppData\Local\Temp\pip-wheel-4pl5gmvp'
       cwd: C:\Users\dell\AppData\Local\Temp\pip-install-mznbfad2\polygon3_cee40c7ea0c6484b9af12f81b433d085\
  Complete output (14 lines):
  NumPy extension not found - disabling support for it!
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build\lib.win-amd64-3.6
  creating build\lib.win-amd64-3.6\Polygon
  copying Polygon\IO.py -> build\lib.win-amd64-3.6\Polygon
  copying Polygon\Shapes.py -> build\lib.win-amd64-3.6\Polygon
  copying Polygon\Utils.py -> build\lib.win-amd64-3.6\Polygon
  copying Polygon\__init__.py -> build\lib.win-amd64-3.6\Polygon
  running build_ext
  building 'Polygon.cPolygon' extension
  error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual C++ Build Tools": http://landinghub.visualstudio.com/visual-cpp-build-tools
  ----------------------------------------
  ERROR: Failed building wheel for Polygon3
  Running setup.py clean for Polygon3
Failed to build Polygon3

我以为就是安装了这两个中的一个就能解决，结果是 Build Tools 安装了依旧提示这个错误，而 Microsoft Visual C++ 14 无法安装，提示错误是你已经安装另外一个版本。

无奈只能去晚上找找 whl 安装包了，大多数推荐的是 https://www.lfd.uci.edu/~gohlke/pythonlibs/ 这个地址，但是我访问的时候已经不行了，最后在华为的镜像站里面找到了下载地址：https://mirrors.huaweicloud.com/repository/pypi/simple/polygon3/。

下载自己需要的版本，这里 cp36 代表 python 版本 3.6，win_amd64 代表 win 64 位。使用下面的命令开始安装：

pip install Polygon3-3.0.8-cp38-cp38-win_amd64.whl

如果提示错误，大概率是没有使用管理员权限运行 cmd。