Re: harder parts of list
- To: mathgroup at smc.vnet.net
- Subject: [mg15599] Re: [mg15570] harder parts of list
- From: BobHanlon at aol.com
- Date: Thu, 28 Jan 1999 04:23:28 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
In a message dated 1/26/99 3:47:55 PM, arnoldk at gauss.cam.wits.ac.za
writes:
>This seems to be a harder list parts problem. Given a list like
>
>lst={{4,2,3,1},{3,1,5},{2,4,3}}
>
>I wish to select the elements in each sublist that are smaller than the
>first
> entry in that sublist.
> So for the above lst the output should be {{2,3,1},{1},{}}. How can I
>do this with Select or Cases?
>
>
>Using pattern matching this works
>
>rule1={a_,b___,c_,d___}:>{a,b,d} /;c>a
>
>
>(# //. rule1)& /@ lst
>
>{{4,2,3,1},{3,1},{2}}
>
>Rest /@ %
>
>{{2,3,1},{1},{}}
>
Arnold,
lst={{4,2,3,1},{3,1,5},{2,4,3}};
little[x_?VectorQ] := Select[Rest[x], # < First[x]&]; little[#]& /@ lst
{{2,3,1},{1},{}}
Bob Hanlon