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Re: Combinations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49827] Re: Combinations
  • From: Paul Abbott <paul at physics.uwa.edu.au>
  • Date: Tue, 3 Aug 2004 01:10:59 -0400 (EDT)
  • Organization: The University of Western Australia
  • References: <ced7i3$q4k$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

In article <ced7i3$q4k$1 at smc.vnet.net>,
 "E. Martin-Serrano" <eMartinSerrano at houston.rr.com> wrote:

> The following seems to be a generalization of David's solution for input of
> any length.
> 
> MyCombinations[list_List]:=
>   Module[{step1},
>  
> step1=Flatten[Outer[List,Sequence@@Array[list&,Length[list]]],Length[list]-1
> ];
>      StringJoin[#1]&/@( Map[SymbolName,#]&/@step1)
>     ]

A slight improvement (using StringJoin in Outer instead of using List):

  MyCombinations[list_List] := 
   With[{n=Length[list]}, Flatten[Outer[StringJoin, 
   Sequence @@ Map[ToString, Table[list, {n}], {2}]], n - 1]]

Cheers,
Paul

-- 
Paul Abbott                                   Phone: +61 8 9380 2734
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