This question already has an answer here:
I'm trying to get ArcGIS 10.1 and Python(x,y) to peacefully co-exist with a unified installation of Python. Surely someone else is using both these tools... right?
Here's where I've gotten to:
VERSION: Since ArcGIS 10.1 uses Python 2.7.2 (which contains NumPy 1.6.1), I went back to the pythonxy install mirrors and found version 220.127.116.11 of Python(x,y) which includes Python 2.7.2 and NumPy 1.6.1.
INSTALL: I crossed my fingers and just installed Python(x,y) after copying my original "C:\Python27\ArcGIS10.1\" folder to a safe location. It installs most of the files at "C:\Program Files (x86)\pythonxy\", and the Python files in "C:\Python27\". This is the same folder where my Arc install of Python lives, except Arc placed its version in the sub-folder "\ArcGIS10.1\". So to recap, I now have a "python.exe" and associated files in "C:\Python27\" as well as "C:\Python27\ArcGIS10.1\".
NEXT? Both Spyder and ArcGIS 10.1 seem to work so far but I'm guessing this won't last long. Two separate installs on the same machine seems like a bad move in principle. I wonder: Is it possible to change Arc's preferences to point to the version in the parent folder, and condense versions? I've gone through folder by folder and in almost every case the Python(x,y) install includes all the files that ArcGIS 10.1 Python does (and then some). The exception is that the Arc install sometimes includes '.pyc' and '.pyo' versions of some '.py' files. But I'm guessing this isn't a critical difference since both directories contain the actual '.py' file.)
Forgot to mention: I added "C:\Python27\ArcGIS10.0\" to the list of system paths, per the instructions in Method 2 at http://forums.arcgis.com/threads/34418-is-it-possible-to-install-other-python-distributions-on-top-of-the-arcgis. I really don't know what this does, just experimenting here.
I may post the same question at forums.arcgis.com, so if interested in the answer check there too.
I tried to add 'python(x,y)' as a tag but was unable to create a new tag.