pip出错，“No module named ‘pip’”
解决办法：
在pycharm终端(Terminal）中
首先执行 ：python -m ensurepip
然后执行 ：python -m pip install --upgrade pip
pip升级或卸载某模块时（如 pip3 install --ignore-installed --upgrade scipy）如果出现下列报错：
Cannot uninstall 'xxx'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
可通过添加' --ignore-installed'解决
pip3 install --ignore-installed --upgrade scipy
