如何在 Ubuntu 18.04 中将 Python 的所有内容完全重置为默认值？

Question

Edit:

So now which pip , which python and which python3 have started working correctly somehow. I was also able to install libraries using pip. The only remaining problem is that of the apt_pkg. Running apt-get install python-apt gives:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
python-apt is already the newest version (1.6.3ubuntu1).

Running any python application still gives error: ImportError: No module named apt_pkg

Running echo $PATH returns:

/home/hamza/bin:/home/hamza/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

Running find /usr -name python -o -name python3 returns:

/usr/local/lib/python3.5/dist-packages/notebook/static/components/codemirror/mode/python
/usr/local/lib/python2.7/dist-packages/notebook/static/components/codemirror/mode/python
/usr/lib/python3
/usr/lib/gimp/2.0/python
/usr/lib/libreoffice/share/Scripts/python
/usr/lib/virtualbox/sdk/bindings/xpcom/python
/usr/lib/wx/python
/usr/bin/python
/usr/bin/python3
/usr/share/code/resources/app/extensions/python
/usr/share/bash-completion/helpers/python
/usr/share/bash-completion/completions/python
/usr/share/bash-completion/completions/python3
/usr/share/python
/usr/share/javascript/codemirror/mode/python
/usr/share/python3
/usr/share/lintian/overrides/python
/usr/share/lintian/overrides/python3
/usr/share/gcc-8/python
/usr/share/gdb/python
/usr/share/librevenge/python
/usr/share/doc/python
/usr/share/doc/python3
/usr/share/doc/python-statsmodels/examples/python
/usr/share/playonlinux/python

Original:

Python on my system is a wreck. I have got multiple versions installed. None work properly. Apparently some applications using python are not working either (eg: Unity Tweaks). My python libraries will not install because pip doesn't work, although it says it is already installed

I was trying to install some libraries for python on my system using pip. Turned out pip was not working. I tried to reinstall pip only to learn that pip was already installed. I went through a process of understanding the difference between python and python3 . I have tried enough things and have basically lost track of the things I have done to get the libraries installed. Long story short, pip does not work no matter what, my libraries will not install and consequently my code doesn't run.

Here is some of the things I have already done:

which pip

This return no output

apt-get install python-pip  

Says I have pip already installed

apt-get install python-apt

To resolve ImportError: No module named apt_pkg . It says:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
python-apt is already the newest version (1.6.3ubuntu1).

But the error persists

And countless other stuff I do not remember.

What I want now is simple. I wish to somehow get out of this hassle by resetting all of my python settings and installation to default, and then install the pandas and numpy libraries for my system. Any and all help would be appreciated.

Result for python -m pip -V :

pip 9.0.1 from /usr/lib/python2.7/dist-packages (python 2.7)

Result for python3 -m pip -V :

pip 9.0.1 from /usr/lib/python3/dist-packages (python 3.5)

Answer 1

One of the following commands worked for me:

pip3 install -U pip
python -m pip install -U pip
python3 -m pip install -U pip

Make sure the version of your python3 is 3.6, which is the default version of ubuntu18, then upgrade pip.

export py3_path=`which python3`
rm $py3_path
ln -s `which python3.6` $py3_path
python3 -m pip install -U pip

Or use pyenv to manage multi versions https://github.com/pyenv/pyenv