Krdytkyu

I want to install Scipy (already have Numpy installed). I have Python 3.5.1-3 installed with OS and IDLE3 (3.5.2). When I hit in terminal

sudo pip3 install scipy

It prints out

Traceback (most recent call last):

File "/usr/bin/pip3", line 9, in <module>

from pip import main

ImportError: cannot import name 'main'

I've already tried to reinstall pip3 and restart OS, but it didn't change.
Has pip3 been working weirdly with someone else?

numpy and scipy are in the default repositories of all currently supported versions of Ubuntu. To install numpy and scipy for Python 3.x open the terminal and type:

sudo apt update    

sudo apt install python3-numpy python3-scipy  

For Python 2.x it's:

sudo apt update  

sudo apt install --no-install-recommends python2.7-minimal python2.7 # this line is only necessary for Ubuntu 17.10 and later 

sudo apt install python-numpy python-scipy

While karel may have solved your "install numpy and scipy" problem, what's wrong with pip on your system hasn't been addressed, so you'll probably have more problems with pip going forward.

Looking here, it seems to be a pretty common recent issue with pip 10 on Ubuntu systems. You may find some work arounds on that thread that work for you, but hopefully an update will fix it soon.

The bug is found in pip 10.0.0.

In linux you need to modify file: /usr/bin/pip from:

from pip import main

if __name__ == '__main__':

    sys.exit(main())

to this:

from pip import __main__

if __name__ == '__main__':

    sys.exit(__main__._main())

Use python -m pip install instead of pip install

I started getting this problem after a pip upgrade:

pip install --upgrade --user pip

The pip (resp. pip3) executable is provided by your distro (python-pip package on Ubuntu 16.04).

Therefore, it is not kept up-to date with the pip package itself as you upgrade pip, and may break.

If you just use python -m pip directly, e.g. as in:

python -m pip install --user somepackage

python3 -m pip install --user somepackage

it goes through your Python path and finds the latest version of pip, and executes that file.

It relies on the fact that that file is executable, but that is a very standard type of interface, and therefore less likely to break than the hackier Debian script.

Then I recommend adding the following aliases to your .bashrc:

pip() ( python -m pip "$@" )

pip3() ( python3 -m pip "$@" )

Tested in Ubuntu 16.04 after an update from pip3 9.0.1 to 18.0.

Installing pip from both apt and pip itself can cause this.

In my case, I used Ubuntu's pip package to install pipenv which then installed a newer copy of pip. Now because my shell runs Ubuntu's pip 9 script (to verify run which pip3) and my Python interpreter then imports the pip 10 module, the pip3 command fails. So I want to uninstall one of the two.

It's fair to assume you have the newer pip for a reason. In that case you want to uninstall the older pip like so:

sudo apt remove python3-pip

If you know for sure that you're fine with the older pip and prefer the system package you'll want to uninstall the newer one:

~/.local/bin/pip3 uninstall pip

or failing that

sudo /usr/local/bin/pip3 uninstall pip

My issue ended up being a mismatch between python3.6 and 3.7. The python3.6 installation put a link in /usr/bin/python3 -> /usr/bin/python3.6 even though the system had upgraded to python3.7.

sudo apt purge python-pip

sudo apt purge python3-pip

sudo apt install python3.7 --reinstall

cd /usr/bin

sudo rm python3

sudo ln -s python3.7 python3

python3 --version

pip3 --version

This worked for me:

pip install --upgrade --user pip

By install --upgrade, I mean whatever you're trying to install.