Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2007

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: rule based program for "Deleting repeated members of a list."

  • To: mathgroup at smc.vnet.net
  • Subject: [mg81938] Re: rule based program for "Deleting repeated members of a list."
  • From: Szabolcs Horvát <szhorvat at gmail.com>
  • Date: Sun, 7 Oct 2007 05:30:44 -0400 (EDT)
  • References: <fe7j44$qga$1@smc.vnet.net>

mumat wrote:
> Hi,
> 
> I have a list s={a,b,c,c,d,e,e,f,g,g,g,h,a,b};
> 
> I need to write a program so that it reads the list and ignors
> repeated elements; so it outputs the following:
> 
> RepeatRemover[s]={a,b,c,d,e,f,g,h,a,b};
> 
> I am looking for a rule-based program to do this!
> 
> Any help would be greatly appreciated.

Why do you insist on a "rule-based" solution?

The obvious (and efficient) solution is
First /@ Split[s]

An inefficient replacement-rule-based solution is
s //. {be___, x_, x_, en___} -> {be, x, en}

-- 
Szabolcs


  • Prev by Date: Re: rule based program for "Deleting repeated members of a list."
  • Next by Date: Re: rule based program for "Deleting repeated members of a list."
  • Previous by thread: Re: rule based program for "Deleting repeated members of a list."
  • Next by thread: Re: rule based program for "Deleting repeated members of a list."