[Python-Dev] long(float('nan')) conversion

[Calvin Spealman]

On Jan 4, 2008 8:07 AM, Christian Heimes <lists at cheimes.de> wrote:
> Hello!
>
> Bug http://bugs.python.org/issue1481296 describes a problem where
> long(float('nan')) causes a seg fault on Mac OS X. On other platforms it
> returns 0L, e.g.
>
> Python 2.5.1 (r251:54863, Oct  5 2007, 13:36:32)
> [GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> float('nan')
> nan
> >>> long(float('nan'))
> 0L

I get even more fun results!

Python 2.4.4 (#1, Oct 18 2006, 10:34:39)
[GCC 4.0.1 (Apple Computer, Inc. build 5341)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> l = long(float('nan'))
000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000L
>>> int(l)
0
>>> long(int(l))
0L

> My patch to Python 2.6 adds an explicit check for NaNs to always return
> 0L. It did feel a bit strange but it's the default on some platforms.
> Today an user pointed out that he doesn't like the patch, too.
>
> How should the problem be solved? In my humble opinion
> long(float('nan')) should return 0L in Python 2.5.2 for b/w
> compatibility and raise a ValueError or OverflowError in Python 2.6+.
>
> Christian
>
> _______________________________________________
> Python-Dev mailing list
> Python-Dev at python.org
> http://mail.python.org/mailman/listinfo/python-dev
> Unsubscribe: http://mail.python.org/mailman/options/python-dev/ironfroggy%40gmail.com
>



-- 
Read my blog! I depend on your acceptance of my opinion! I am interesting!
http://ironfroggy-code.blogspot.com/