Message-ID: <OFC39C017A.C6CA6424-ONC125759F.002D551B-C125759F.002DC317@precheza.cz>
Date: 2009-04-21T08:19:57Z
From: PIKAL Petr
Subject: bug when subtracting decimals?
In-Reply-To: <loom.20090421T075616-887@post.gmane.org>
r-help-bounces at r-project.org napsal dne 21.04.2009 10:00:06:
> Petr PIKAL <petr.pikal <at> precheza.cz> writes:
>
> > Maybe that is because of Excel is so widespread now and gives expected
> > results (it probably silently rounds all decimal numbers before
> > calculation).
>
> Marc Schwartz already reminded me of that one, and it's a good point
> to explicitly mention in lectures.
>
> I suggest to extend R by introducing %==% as "being Excellently equal".
It helps but not in all cases
> (0.7-0.3)-.4>0
[1] FALSE
> (0.7-0.3)-.4<0
[1] TRUE
>
There always could be different issues with not exact representation of
decimals. So educated user or internal rounding could help but I am not
sure if later is desired.
Regards
Petr
>
> Dieter
>
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