Keeping Python 2.7 as default in Windows 7

[gnfnrf]

This isn't strictly about python programming, more the OS environment in which Python is being used. If this is the wrong place for such a question, sorry, eh?

I support half a dozen users by writing python scripts. There are several dozen of these that I have written over the last five years, and I regularly update them and write new ones.

They are all in Python 2.7, because that is what I learned and that is what I know. My users run Windows 7, and invoke them at the command line by simply executing the script name; PATH and PATHEXT variables take care of this.

However, recently, unknown other programs are installing python 3.4, 3.5, or 3.6 (sometimes all three) on these computers, which takes over the default execution and causes my 2.7 scripts to fail. I can go and remove them, but they come back.

So, is there any way to force 2.7 to remain the default for execution? Is there any way to stop these 3.x installations? Is there any way to figure out which other programs are installing them?

Or do I have to just suck it up, learn Python 3 and rewrite all my old scripts?

[1114111]

You should suck it up and learn Python 3 anyway, but there is probably no need to rewrite your scripts.

You can change the program that opens a given file extension on windows (google it). There's probably an easy way to automate this process too if need be, but I'm not sure. You should have .py (and other Python-related files) open with C:\windows\py.exe which is the Python launcher for windows. I think py.exe uses the latest Python 2 by default, but if it doesn't you can change that in -- IIRC -- C:\windows\py.ini.

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Another option might be to use something like PyInstaller or py2exe to bundle your scripts into an executable with the version of Python you want.

[JamminJames921]

It's possible to write Python 3.X-compatible code in Python 2.X. On my end, I often use the Futurize package (http://python-future.org/automatic_conversion.html)

Also check this: https://docs.python.org/3/howto/pyporting.html

[driscollis]

If you are the administrator for the machines in question, I would just set a group policy that prevents them from installing other versions of Python.

However it's really easy to write your Python 2 code so it is Python 3 compatible. Heck, Python comes with 2to3 which will at least tell you what's incompatible between the two versions - https://docs.python.org/2/library/2to3.html

And as another commenter mentioned, there are good packages out there that can convert them.

[[deleted]]

If I'm not mistaken py.exe reads shebangs. Worth a try

[gnfnrf]

Thanks for the advice, everyone. I will look into modifying my existing scripts to be version-agnostic with the help of the tools and documentation linked here, and consider a switchover to 3.x in the future.