How to change default Python path to 2.6 from 2.7.2 on iMac OSX Lion 10.8.5?

Question

I need to install Scipy, Numpy, Scikit-Learn on my iMac, which runs on OSX Lion 10.8.5, the default Python is 2.7.2. I have downloaded Scipy, Numpy, Scikit-learn, but could not install them because my default Python is 2.7.2

I understand 4 versions of Python 2.3, 2.5, 2.6, 2.7 are present on my iMac. Wonder how to change my default Python to 2.6 ?

Thanks

Tian

Answer 1

I'm not familiar with Mac, but in Linux (and some other unixes), running such a command as root will set the default python executable to 2.6

cd $(dirname $(which python))
ln -sf python2.6 python

Answer 2

A quick shift between standard python versions on OSX

$: defaults write com.apple.versioner.python Version 2.5
$: python -V

#   [ Output ]
#   Python 2.5.6

$: defaults write com.apple.versioner.python Version 2.7
$: python -V

#   [ Output ]
#   Python 2.7.5

System-wide python Preferences

This preferences for python-apple are set on User basis. To set the default python version system wide, we write into /Library/Preferences/com.apple.versioner.python. You must be admin to do so.

$: sudo defaults write /Library/Preferences/com.apple.versioner.python Version 2.5

If we decide to set the default python version system-wide, we should be able to define a user-specific python default version as well.

The environment variable VERSIONER_PYTHON_VERSION

We can use the environment variable VERSIONER_PYTHON_VERSION in addition to our preferences. This environment variable takes precedence over settings in preferences files!

$: export VERSIONER_PYTHON_VERSION=2.5
$: python -V

#   [ Output ]
#   Python 2.5.6