Re: Sorting 3 points
- To: mathgroup at smc.vnet.net
- Subject: [mg87988] Re: [mg87935] Sorting 3 points
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 21 Apr 2008 14:35:47 -0400 (EDT)
- Reply-to: hanlonr at cox.net
p = {P1,P2,P3};
Sort[p, #1[[3]] < #2[[3]] &]
Sort[p, Last[#1] < Last[#2] &]
Bob Hanlon
---- carlos at Colorado.EDU wrote:
> Simple question, but documentation is no help.
> I have three coordinate triplets:
>
> P1={x1,y1,z1} P2={x2,y2,z2} P3={x3,y3,z3}
>
> where all entries are numeric. I wont to sort them into
>
> P1s={xs1,ys1,zs1} P2s={xs2,ys2,zs2} P3s={xs3,ys3,zs3}
>
> so that zs3>=zs2>=zs1, with one command
>
> {P1s,P2s,P3s}=Sort[{P1,P2,P3}, Ordering Function]
>
> Is that possible and if so, which Ordering Function
> should be used? Thanks.
>