[Tutor] Checking for Python version

[Todd Zullinger]

Christian Witts wrote:
> Your version will fail if the person is running Python 3.0, 3.1 up
> until the 3.3 series which is not good.  Neater looking (imo) code
> below.
>
> from sys import version_info, exit
>
> if version_info[0] == 1 or (version_info[0] == 2 and version_info[1] < 4):
>    exit("Please upgrade to Python 2.4 or greater.")

This would fail on python < 2.0, as version_info is not available.  So
you'd want to catch that, if you want to gracefully handle ancient
versions of python.  You could also just compare the version_info
tuple.

This is a bit ugly, but it works at least back to 1.5.2:

import sys

min_version = '2.4'
upgrade_msg = 'Please upgrade to Python %s or greater' % min_version

try:
    min = tuple(map(int, min_version.split('.')))
    ver = sys.version_info[:3]
    if ver < min:
        sys.exit(upgrade_msg)
except AttributeError:
    sys.exit(upgrade_msg)

I don't have any python 3.x systems to test though.

-- 
Todd        OpenPGP -> KeyID: 0xBEAF0CE3 | URL: www.pobox.com/~tmz/pgp
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Suppose I were a member of Congress, and suppose I were an idiot. But,
I repeat myself.
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