python/pip坏解释器:没有这样的文件或目录

我好像把Mac上所有的Python包都丢了。

我输入以下命令以从python3.6升级到python3.7:

brew upgrade python

现在当我进入 ipython3 在终端上写着:

-bash: /usr/local/bin/ipython3: /usr/local/opt/python/bin/python3.6: bad interpreter: No such file or directory

但是我能用 iPython 3 在我执行brew升级之前。此外,我想我已经丢失了所有的python包,因为当我在python3中执行导入模块时,它会说:

ModuleNotFoundError: No module named *examplepythonpackage*

我以前安装的python包是否永远丢失了?我现在是否必须单独重新安装它们?

我也不能(在bash终端)运行$ iPython 3

-bash:/usr/local/bin/ipython3:/usr/local/opt/python/bin/python3.6:错误的解释器:没有这样的文件或目录

供参考:

$ which python
    /usr/bin/python
$ which python3
    /usr/local/bin/python3
$ pip --version
    pip 18.1 from /Library/Python/2.7/site-packages/pip-18.1-py2.7.egg/pip (python 2.7)
$ pip3 --version
    pip 18.1 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)