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MathGroup Archive 2000

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Re: Re: Sorting

  • To: mathgroup at smc.vnet.net
  • Subject: [mg22157] Re: [mg22110] Re: [mg22067] Sorting
  • From: "Christopher French" <clfrench at msn.com>
  • Date: Wed, 16 Feb 2000 02:35:24 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Wagner,

Here is a more fundamental solution for canonical ordering of alphanumeric
structures that are symbols or strings.

 Sort[{z2, a5, z10}, (OrderedQ[Characters/@ToString/@{##}]&) ]&

Christopher Lee French
<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>
The secret of magnetism, now explain that to me!
There is no greater secret, except love and hate.

                               Johann Wolfgang Von Gothe
-----Original Message-----
From: Christopher French <clfrench at msn.com>
To: mathgroup at smc.vnet.net
Subject: [mg22157] [mg22110] Re: [mg22067] Sorting


>Wagner,
>
>I know that you already received several answers to you post but this
seemed
>like such a fun problem that I could not resist. You are trying to get Sort
>to ignore digit strings while sorting lists of strings that represent
>symbols. One way to do this is to create a function for Sort to use on your
>input. For example
>
>Sort[ {"z2", "a5", "z10"}, (OrderedQ[{#2, #1}]&)]
>
>will cause your result to be the same as
>
>Reverse[ Sort[ {"z2", "a5", "z10"} ] ].
>
>For your situation you want sorting to proceed as normal on elements with
>the number strings stripped from the arguments. This is the result that you
>gave in your example.
>
> Sort[{"z2","a5","z10"}]
>
>{"a5","z10","z2"}
>
>This is a function that you can give to Sort that will strip the digits
from
>the strings (in place) before testing them.
>(please excuse the eccentric programming style, I tent to prefer writing
>post-fix pure functions)
>
> noDigits=
> {##}
>   //Characters/@#&
>   //DeleteCases[#,_?DigitQ]&/@#&
>   //StringJoin@@#&/@#&
>   //OrderedQ
>   //Function;
>
>This is the same pure function using prefix notation.
>
>noDigits=
>OrderedQ[
>((StringJoin@@#&)/@#&)[
>((DeleteCases[#,_?DigitQ]&)/@#&)[
>(Characters/@#&)[{##}]]]]&;
>
>Now, Sort gives the output that matches the kind that you requested.
>
>Sort[{"z2","a5","z10"}, noDigits]
>{"a5","z2","z10"}
>
>Christopher Lee French
><<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>
>The secret of magnetism, now explain that to me!
>There is no greater secret, except love and hate.
>
>                               Johann Wolfgang Von Gothe
>-----Original Message-----
>From: Wagner Truppel <wtruppel at uci.edu>
To: mathgroup at smc.vnet.net
>To: mathgroup at smc.vnet.net
>Subject: [mg22157] [mg22110] [mg22067] Sorting
>
>
>>Hi folks,
>>
>>can anyone tell me how I can make Mathematica sort variable names
>>without sorting any numbers within those variables as strings as
>>well? If you try Sort[{z2,a5,z10}] you get back {a5,z10,z2}, while I
>>want to get back {a5,z2,z10}.
>>
>>Thanks.
>>Wagner Truppel
>>wtruppel at uci.edu
>>
>>
>>
>
>
>
>
>
>





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