Re: Sort with -Infinity fails
- To: mathgroup at smc.vnet.net
- Subject: [mg73872] Re: [mg73822] Sort with -Infinity fails
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 2 Mar 2007 06:37:27 -0500 (EST)
- Reply-to: hanlonr at cox.net
The default ordering function used in Sort is OrderQ
Sort[{5,-Infinity,-8}]
{-8, 5, -Infinity}
OrderedQ[%]
True
Sort[{5,-Infinity,-8},OrderedQ[{##}]&]==%%
True
OrderedQ[{-Infinity,-8,5}]
False
Use Less for the ordering function
Sort[{5,-Infinity,-8},Less]
{-Infinity, -8, 5}
Use Greater for the reverse order
Sort[{5,-Infinity,-8},Greater]
{5, -8, -Infinity}
Bob Hanlon
---- Tom Aldenberg <Tom.Aldenberg at rivm.nl> wrote:
> Dear MathGroup,
>
> Minus Infinity (-Infinity) is smaller than -8, but Sort does not sort it =
as
> expected.
> Is there a Real minus Infinity?
>
>
> In[75]:=
> -Infinity < -8
> Out[75]=
> True
>
> In[76]:=
> Sort[{-Infinity, -8, 5}]
> Out[76]=
> {-8, 5, -=1B$B!g=1B(B}
>
>
> Regards,
>
> Tom Aldenberg
>
> _________________________________________________________________________=
___
>
> DISCLAIMER: http://www.rivm.nl/disclaimer.htm
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