【nbextensions模块安装失败解决】 which is required to install pyproject.toml-based projects...

安装jupyter_contrib_nbextensions时报错：

ERROR: Could not build wheels for jupyter_contrib_nbextensions, which is required to install pyproject.toml-based projects

仔细该错误是由 

error: could not create 'build\bdist.win-amd64\wheel\.\jupyter_contrib_nbextensions\nbextensions\contrib_nbextensions_help_item\contrib_nbextensions_help_item.yaml': No such file or directory
      [end of output]

引起的，如图所示

 发现是文件夹名字太长，无法建立有效路径，需要更改注册表，

在win+r，输入 regedit，然后设置：
\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem路径下的变量 LongPathsEnabled, 将其置为 1，重新运行pi'p即可