Re: position lists
- To: mathgroup at smc.vnet.net
- Subject: [mg68737] Re: position lists
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Thu, 17 Aug 2006 04:18:47 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 8/16/06 at 3:36 AM, rychphd at gmail.com (rych) 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? Other than In[4]:= (Flatten[Position[a, #1]] & ) /@ Range[4] /. {} -> {0} Out[4]= {{1,2,5},{3,4},{0},{6}} no -- To reply via email subtract one hundred and four