Re: Word permutations - frustrated by lists.
- To: mathgroup at smc.vnet.net
- Subject: [mg71713] Re: Word permutations - frustrated by lists.
- From: dh <dh at metrohm.ch>
- Date: Mon, 27 Nov 2006 04:04:35 -0500 (EST)
- References: <ekbrks$jga$1@smc.vnet.net>
Hi,
the easy way to get permutations is:
<< DiscreteMath`Combinatorica`
Permutations[{"d", "e", "a", "r"}]
Daniel
wooks wrote:
> Hello. Am relatively new with Mathematica.
>
> I seem to have a general problem with results that look right but for
> embedded lists. Here is an example of my problem. This is supposed to
> be a algorithm to generate all permutations of a string. T
>
> Clear[arrangements]
> arrangements[str_String /; StringLength[str] == 1] := {str};
> arrangements[str_String] := (Prepend[arrangements[StringJoin[
> Rest[#]]]], First[#]) & /@
> NestList[RotateRight, Characters[str], StringLength[str] - 1];
> arrangements["dear"]
>
> PS This is not homework. I'm rewriting some examples from another
> programming book as as practice for Mathematica.
>