我安装了全新的python 3.7.1 64位安装程序，并且使用最新的pyCharm作为我的IDE。我在这台机器上没有其他的python安装。
我去安装numpy并收到以下消息：
(venv) C:\Users\John\PycharmProjects\project>pip install numpy
Requirement already satisfied: numpy in c:\users\john\pycharmprojects\pysims\venv\lib\site-packages (1.15.4)
You are using pip version 10.0.1, however version 18.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
所以我运行了建议的命令，但是它已经是最新的
(venv) C:\Users\John\PycharmProjects\project>python -m pip install --upgrade pip
Requirement already up-to-date: pip in c:\users\john\pycharmprojects\pysims\venv\lib\site-packages (18.1)
所以我检查了版本，但仍然是旧版本
(venv) C:\Users\John\PycharmProjects\pySIMS>pip -V
pip 10.0.1 from c:\users\john\pycharmprojects\pysims\venv\lib\site-packages\pip-10.0.1-py3.7.egg\pip (python 3.7)
我以为我会尝试py -3进行升级，并且可以正常工作。
(venv) C:\Users\John\PycharmProjects\pySIMS>py -3 -m pip install --upgrade pip
Collecting pip
Using cached https://files.pythonhosted.org/packages/c2/d7/90f34cb0d83a6c5631cf71dfe64cc1054598c843a92b400e55675cc2ac37/pip-18.1-py2.py3-none-any.whl
Installing …