pip无法正常使用卸载并重新安装

错误提示

➜  ~ pip
Traceback (most recent call last):
  File "/usr/bin/pip", line 11, in <module>
    load_entry_point('pip==10.0.1', 'console_scripts', 'pip')()
  File "/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 476, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2700, in load_entry_point
    return ep.load()
  File "/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2318, in load
    return self.resolve()
  File "/usr/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2324, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/usr/lib/python3.6/site-packages/pip/_internal/__init__.py", line 42, in <module>
    from pip._internal import cmdoptions
  File "/usr/lib/python3.6/site-packages/pip/_internal/cmdoptions.py", line 16, in <module>
    from pip._internal.index import (
  File "/usr/lib/python3.6/site-packages/pip/_internal/index.py", line 20, in <module>
    from pip._vendor.requests.exceptions import SSLError
ModuleNotFoundError: No module named 'pip._vendor.requests.exceptions'

问题分析

系统是Manjaro Linux，pip是通过包管理器pacman安装的，这个应该是包管理器安装的pip出现了问题。
卸载试试。看看能不能在安装后换回包管理器版本的pip，因为这样子系统很干净。

解决方案

1. 卸载pip sudo pacman -R python-pip
2. 下载最新的pip源码包当前为10.0.1，wget https://files.pythonhosted.org/packages/ae/e8/2340d46ecadb1692a1e455f13f75e596d4eab3d11a57446f08259dee8f02/pip-10.0.1.tar.gz
3. 解压tar -zxvf pip-10.0.1.tar.gz && cd pip-10.0.1
4. 安装pipsudo python3 setup.py install
5. 安装pip完成
   如果你没有系统洁癖，强迫症到这里就完成了。
   这样子安装的pip无法通过包管理器完成更新，每次需要手动更新。
6. 卸载pipsudo python -m pip uninstall pip
7. 重新安装pipsudo pacman -S python-pip