Pip does not work after upgrade to ubuntu-16.10

问题:

Running a command alongwith pip gives the following error. Even the command pip -V produces the following error.
I read that the error is due to setuptools version 31.0.0 and it should be lower than 28.0.0. But the version of my setuptools is 26.1.1 and it still gives the same error.

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 7, in 
    from pip import main
  File "/usr/local/lib/python3.5/dist-packages/pip/__init__.py", line 26, in 
    from pip.utils import get_installed_distributions, get_prog
  File "/usr/local/lib/python3.5/dist-packages/pip/utils/__init__.py", line 27, in 
    from pip._vendor import pkg_resources
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3018, in 
    @_call_aside
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3004, in _call_aside
    f(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3046, in _initialize_master_working_set
    dist.activate(replace=False)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2578, in activate
    declare_namespace(pkg)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2152, in declare_namespace
    _handle_ns(packageName, path_item)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2092, in _handle_ns
    _rebuild_mod_path(path, packageName, module)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2121, in _rebuild_mod_path
    orig_path.sort(key=position_in_sys_path)
AttributeError: '_NamespacePath' object has no attribute 'sort'

回答1:

The only solution I could find is reinstalling pip. Run these commands on your terminal

• wget https://bootstrap.pypa.io/get-pip.py
• sudo -H python get-pip.py --prefix=/usr/local/

However, this works only for pip, not pip3!

回答2:

Upgrade your setuptools: wget https://bootstrap.pypa.io/ez_setup.py -O - | sudo python3

Generally sudo combined with pip is considered harmful, avoid this when your system is not already broken.

回答3:

Please refer to https://stackoverflow.com/a/48126778/7596504. The problem could be fixed by modifying your /usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py.