How to list all modules python 2.7 and 3.4 have installed for MacOSX - macos

Question

How do I make all modules be available for both python 2.7 and 3.4?
I executed:
$ brew install <prerequisites for pygame>
<snip snip>
<snip snip>
$ brew install pygame
$ pip freeze
<snip snip>
pygame==1.9.2a0
<snip snip>
and can see pygame is installed. When I open a new shell/terminal and run python 2.7 and type import pygame, I have no problems:
Python 2.7.9 |Anaconda 2.2.0 (x86_64)| (default, Dec 15 2014, 10:37:34)
[GCC 4.2.1 (Apple Inc. build 5577)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Anaconda is brought to you by Continuum Analytics.
Please check out: http://continuum.io/thanks and https://binstar.org
>>> import pygame
>>>
However, when I run python 3.4 and type import pygame, it says there's no module named pygame.
/usr/local/bin/python3
Python 3.4.2 (default, Dec 11 2014, 17:48:01)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.56)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pygame
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named 'pygame'
>>>
What do I need to do to make 3.4 see/link with all the modules that 2.7 sees?
P.S. I don't know how but pip is running from anaconda, which I think I might have installed when installing numpy or panda or something.

Answer 1

You cannot use modules installed for Python 2 in Python 3. Python 2 and Python 3 are not compatible, that is why most libraries offer a Python 2 and a Python 3 version.
So if you have PyGame installed with pip2, you can only use it with Python 2. To use PyGame in Python 3, you need to install it with pip3. Afterwards you will have both versions on your computer, so that a project that uses your Python 2 interpreter uses the PyGame installed by pip2 and a project that uses Python 3 interpreter uses the pyGame installed by pip3.
Example:
# test.py
import pygame
In the console:
> python3 test.py # imports pygame from /usr/lib/Python3.x/site-packages
> python2 test.py # imports pygame from /usr/lib/Python2.x/site-packages

Answer 2

You should not use Python 2 modules with Python 3 (and vice versa). Instead, install those separately, e.g.
pip3 install pygame
Sometimes, the code bases for a package will be compatible between 2 and 3, but quite often, they are not (especially when shared object modules, *.so files, come into play).
Also, Python 2 will not have the Python 3 packages library in sys.path by default, and vice versa. For a good reason.
All in all, consider Python 2 and Python 3 two different languages, for which you have to do everything separately. They just happen to be very much alike.
(Personal opinion/bit of advocacy: use and write your code in Python 3, unless you have a very good reason no to (unported essential libraries, chance of losing your job). It's relatively straightforward in 99% of the cases to make it Python 2 compatible later on, if really needed.)