Python:为什么每当我想安装东西时它总是要求安装 pyparsing？

Question

我不确定为什么 pip 总是抛出“找不到 pyparsing”的异常。即使当我尝试下载 pyparsing 时，我也会得到:

pip install pyparsing
Traceback (most recent call last):
  File "/usr/bin/pip", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 72, in <module>
    import packaging.requirements
  File "/usr/local/lib/python2.7/dist-packages/packaging/requirements.py", line 9, in <module>
    from pyparsing import stringStart, stringEnd, originalTextFor, ParseException
ImportError: No module named pyparsing

这没有意义？!

Answer 1

即使我按照 Shahin 和 Paul 所说的做了，我仍然会遇到同样的错误。所以我删除了 pip 并重新安装它:

sudo apt-get purge python-pip
curl "https://bootstrap.pypa.io/get-pip.py" -o "get-pip.py"
python get-pip.py