Re: position lists
- To: mathgroup at smc.vnet.net
- Subject: [mg68706] Re: [mg68688] position lists
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 17 Aug 2006 04:18:13 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
a = {1, 1, 2, 2, 1, 4};
Flatten/@(Position[a,#]&/@
Range[Max[a]])/.{}:>{0}
{{1,2,5},{3,4},{0},{6}}
Bob Hanlon
---- rych <rychphd at gmail.com> wrote:
> have
> In: a = {1, 1, 2, 2, 1, 4}
> want
> {{1, 2, 5}, {3, 4}, {0}, {6}};
>
> more effectively than just
> In: Position[a, #] & /@ Range[4]
> Out: {{{1}, {2}, {5}}, {{3}, {4}}, {}, {{6}}}
>
> Ideas? Known one-liners?
> Thanks
> Igor
>