[erlang-questions] Inf, NaN, and -Inf

Håkan Nilsson <>
Mon Feb 27 18:37:25 CET 2012


Why would you do it with a complicated foldl instead of just
lists:max(List) and lists:min(List)?

On Mon, Feb 27, 2012 at 6:26 PM, Matthew Evans <>wrote:

>
> You can use lists:sort/1
>
> > List = [7.1,2.2,1.1,5.7,2].
> [7.1,2.2,1.1,5.7,2]
> 2> Sorted = lists:sort(List).
> [1.1,2,2.2,5.7,7.1]
> 3> hd(Sorted).
> 1.1
> 4> lists:last(Sorted).
> 7.1
>
> Or using lists:fold/3:
>
> 5> lists:foldl(fun(Val,{Min,Max}) ->
> {erlang:min(Val,Min),erlang:max(Val,Max)} end,
> {erlang:hd(List),erlang:hd(List)}, List++[2.1]).
> {1.1,7.1}
>
> Matt
> ----------------------------------------
> > Date: Mon, 27 Feb 2012 11:07:53 -0600
> > From: 
> > To: 
> > Subject: [erlang-questions] Inf, NaN, and -Inf
>
> >
> > So in python and C to find the biggest and smallest number in a list
> > of floating point numbers I'd do something like a lists:foldl and
> > simply give it
> >
> > inf and -inf respectively as the values to compare against, or better
> > yet use some built in defines or variables defining what the min and
> > max values for a particular number type are.
> >
> > Is there some sane way to do this in erlang? Is there a way to get the
> > floating point values inf and -inf in erlang or the maximal and
> > minimal values for integers and floats in erlang? I didn't see it in
> > my hunt around the documentation perhaps I just missed it.
> >
> > Thanks!
> >
> > Tom
> > _______________________________________________
> > erlang-questions mailing list
> > 
> > http://erlang.org/mailman/listinfo/erlang-questions
>
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> 
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>


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Håkan Nilsson

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