Fix Python – ipython reads wrong python version

Question 1

I’ve been having trouble with Python, iPython and the libraries. The following points show the chain of the problematics. I’m running Python 2.7 on Mac Lion.

iPython doesn’t read the libraries of scipy, matplotlib, but it does read numpy.
To fix this, I tried installing Python’s source code version, and it only gave me more problems since now I have two different versions: 2.7.1 and 2.7.2
I noticed that running Python, uses version 2.7.2 and does import scipy, matplotlib, and numpy, but on iPython the version is 2.7.1 which doesn’t open scipy or matplotlib.

I’ve tried several things that I’ve encountered from other blogposts. But none of them have helped, and also unfortunately I don’t quite know what I’m doing with some of them. For example:
I tried uninstalling and reinstalling ipython with easy_install and pip. I also tried reinstalling everything through homebrew, and modifying the path .bash_profile.

Question 2

Okay quick fix:

which python

gives you /usr/bin/python, right? Do

which ipython

and I bet that’ll be /usr/local/bin/ipython. Let’s look inside:

Edit 9/7/16 — The file now looks like this:

cat /usr/local/bin/ipython

#!/usr/bin/python

# -*- coding: utf-8 -*-
import re
import sys

from IPython import start_ipython

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(start_ipython())

And mine works properly like this, but my situation isn’t exactly like the OP’s.

Original answer — 9/30/13:

cat /usr/local/bin/ipython

#!/usr/bin/python
# EASY-INSTALL-ENTRY-SCRIPT: 'ipython==0.12.1','console_scripts','ipython'
__requires__ = 'ipython==0.12.1'
import sys
from pkg_resources import load_entry_point

if __name__ == '__main__':
    sys.exit(
        load_entry_point('ipython==0.12.1', 'console_scripts', 'ipython')()
    )

Aha – open /usr/local/bin/ipython in your editor (with privileges), and change the first line to

#!/usr/local/bin/python

save, start iPython, should say it’s using the version you want now.

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