Ubuntu – Using pip3-installed python 3 packages when apt-installed packages exist too


I have numpy 1.8.2 installed in /usr/lib/python3/dist-packages (via apt), and the newest version (1.9.2) installed in /usr/local/lib/python3.4/dist-packages (via pip). Both paths are in sys.path (in that order), but only the older apt version is getting imported in python3.

➜  ~  sudo pip3 install --upgrade numpy
[sudo] password for naught101: 
Real name of requirement numpy is numpy
Requirement already up-to-date: numpy in /usr/local/lib/python3.4/dist-packages
Cleaning up...
➜  ~  ipython3
Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
Type "copyright", "credits" or "license" for more information.

IPython 1.2.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import numpy

In [2]: numpy.version
Out[2]: <module 'numpy.version' from '/usr/lib/python3/dist-packages/numpy/version.py'>

In [3]: 

In [3]: numpy.version.version
Out[3]: '1.8.2'

In [5]: import sys

In [6]: sys.path

(python3 does the same thing as ipython3 here)

How can I get python3 to use the newer version?

I can't just uninstall the apt version, because other packages depend on it.

Best Answer

This blog post explain the code logic behind this very well: How does python find packages?

Quoting it:

As the docs explain, sys.path is populated using the current working directory, followed by directories listed in your PYTHONPATH environment variable, followed by installation-dependent default paths, which are controlled by the site module.

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