Re: position lists
- To: mathgroup at smc.vnet.net
- Subject: [mg68739] Re: position lists
- From: "dkr" <dkrjeg at adelphia.net>
- Date: Thu, 17 Aug 2006 04:18:50 -0400 (EDT)
- References: <ebujvu$6lu$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In[22]:=
a = {1, 1, 2, 2, 1, 4} ;
In[23]:=
Flatten[Reap[MapIndexed[Sow[#2[[1]],#1]&,a],Range[4]][[2]]/.{}:>{{0}},1]
Out[23]=
{{1,2,5},{3,4},{0},{6}}
In[24]:=
b=Reverse[a]
Out[24]=
{4,1,2,2,1,1}
In[25]:=
Flatten[Reap[MapIndexed[Sow[#2[[1]],#1]&,b],Range[4]][[2]]/.{}:>{{0}},1]
Out[25]=
{{2,5,6},{3,4},{0},{1}}
dkr