Re: List difference using patterns and substitutions.
- To: mathgroup at smc.vnet.net
- Subject: [mg71334] Re: [mg71306] List difference using patterns and substitutions.
- From: Mark Teagarden <Mark.Teagarden at utsa.edu>
- Date: Wed, 15 Nov 2006 06:43:38 -0500 (EST)
Nacho,
Something like this?
a = {1,2,4,7,11,16};
out = Drop[a,1]-Drop[a,-1]
Mark
On 11/14/06 4:06 AM, "Nacho" <ncc1701zzz at gmail.com> wrote:
> Hello.
>
> I'm trying to figure how can I build a difference list from another
> using only patterns and rule substitutions.
>
> The idea is to get from a list, another, one element shorter, where
> each value is the substraction of two consecutive elements in the
> original list, that is, from {1,2,3,5,5} get {1,1,2,0}.
>
> I've been thinking about it for a while, and I know several methods
> using a more traditional programming style (with For, for example), but
> I have no idea if it is possible to make it simple and fast with rule
> substitutions.
>
> Any idea?
>
> Thanks in advance.
>
--
Mark A. Teagarden, Ph.D.
University of Texas at San Antonio
Department of Biology
One UTSA Circle
San Antonio, TX 78249
Phone: 210.458.4746
FAX: 210.458.5658