Teething troubles with Python on a Mac

Thomas Philips tkpmep at gmail.com
Sun Aug 3 04:41:03 CEST 2008

I've got a new iMac, have installed Python 2.5.2 on it, and am now
trying to run my existing Python programs on it (these are typically
number crunching programs that I run from IDLE). Some things work,
while others don't, and as this is my first time grappling with Unix
and MacOS X, I appreciate some guidance on how to get up and running.
Here are details of my setup interspersed with my woes and my
questions. Your assistance is greatly appreciated.

Item 1. I downloaded and installed 2.5.2 from python.org. Runs fine,
it installed a MacPython directory under applications, which has a few
icons, including IDLE. However, I have absolutely NO idea where all
the Python files are kept.

Question 1: How can I locate the Python installation? There a few
files under Applications > MacPython 2.5, but this is clearly not the
entire installation.

Question 2: In Finder, If I click on Search For > Past week, I can see
a sequence of folders under the horizontal scroll bar at the bottom of
the window, allowing me to determine that some files that were placed
under Applications > MacPython 2.5> Extra> Demo. But I do not seem to
be able to see the sequence of folders under the horizontal scroll bar
in any finder window. What do I need to do to make the folder sequence
visible in all Finder Windows?

Item 2. I downloaded and installed the SciPy superpack from
Macinscience,org. Scipy seems to import correctly into the Python
2.5.1 that comes with the Mac, but i cannot import it into MacPython

Question 3. What do I have to do in order to make SciPy work with both
Python 2.5.1 (that comes with the Mac) and 2.5.2 (that I installed

Item 3. I accidentally clicked on something (not sure what) and
suddenly found the path to the numpy folder was Macintosh HD >
Developer > SDKs > MacOSX10.5.sdk>System>
This is insane!!! Where would the superpack have installed SciPy, and
how can I find it?

Question 4. How do I get MacPython 2.5.2 to see SciPy, NumPy etc.
Question 5. How can I find the current value of the PYTHONPATH
environment variable, and how can I edit it and add a directory in
which I keep my Python programs.
Question 6. Apparently there's a Property List Editor that must be
used to create a file called ~ /.MacOSX/environment.plist. I can't
find a directory called ~/.MacOSX. Is this a hidden directory?

Item 4. I opened a terminal window, and typed ipython. Here's what I

Welcome to IPython. I will try to create a personal configuration
where you can customize many aspects of IPython's functionality in:

Installation error. IPython's directory was not found.

Check the following:

The ipython/IPython directory should be in a directory belonging to
PYTHONPATH environment variable (that is, it should be in a directory
belonging to sys.path). You can copy it explicitly there or just link
to it.

IPython will create a minimal default configuration for you.
Ipython actually runs once I hit enter, but I do not seem to be able
to import and run my programs.

Question 7. What is this cryptic message all about? I'm completely

I never thought I'd say this, but it actually seemed a lot easier to
get Python and any associated programs up and running on Windows! I
suspect that a large fraction of my troubles are due to the fact that
I am brand new to the Mac and to Unix, but I bought the Mac in part
because I thought that using it was effortless.

Thank you in advance for your help.


Thomas Philips

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