[Python-Dev] trunc()

Jeroen Ruigrok van der Werven asmodai at in-nomine.org
Fri Jan 25 20:35:20 CET 2008


[I am still recovering, so if I say something totally misinformed I blame my
recovery. :) ]

-On [20080125 15:12], Christian Heimes (lists at cheimes.de) wrote:
>Python 3:0
>
> 2.4 ( 2,  3,  2,  2,  2)
> 2.6 ( 2,  3,  3,  2,  2)
>-2.4 (-3, -2, -2, -2, -2)
>-2.6 (-3, -2, -3, -2, -2)
>
>Python 2.6:
> 2.4 ( 2.0,  3.0,  2.0,  2,  2)
> 2.6 ( 2.0,  3.0,  3.0,  2,  2)
>-2.4 (-3.0, -2.0, -2.0, -2, -2)
>-2.6 (-3.0, -2.0, -3.0, -2, -2)

Am I the only one who wonders about the sudden change in decimal significance?
Especially given the fact that the ISO C standard specifies floor(), for
example, as returning a floating point value and the above in Python 3.0
deviates to just returning an integer. Which is also different from 2.5's
behaviour.

Can I assume we are all familiar with the concept of significant digits and
that we agree that from this point of view 2 != 2.0? And that results such as
the above would be a regression and loss in precision?

-- 
Jeroen Ruigrok van der Werven <asmodai(-at-)in-nomine.org> / asmodai
イェルーン ラウフロック ヴァン デル ウェルヴェン
http://www.in-nomine.org/ | http://www.rangaku.org/
We have met the enemy and they are ours...


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