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From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: comp.lang.perl
Subject: Re: sort -uniq in perl?
Message-ID: <1990Sep8.051241.6192@iwarp.intel.com>
Date: 8 Sep 90 05:12:41 GMT
References: <CKD.90Sep7212420@bucsf.bu.edu> <CKD.90Sep7213500@bucsf.bu.edu> <1990Sep8.023805.29123@agate.berkeley.edu>
Sender: news@iwarp.intel.com
Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 29
In-Reply-To: raymond@math.berkeley.edu (Raymond Chen)

In article <1990Sep8.023805.29123@agate.berkeley.edu>, raymond@math (Raymond Chen) writes:
| In article <CKD.90Sep7213500@bucsf.bu.edu>, ckd@cs (Christopher Davis) writes:
| >Well, I went back and hacked this little thing up, but I'm still open to
| >suggestions for a better way to do it.
| 
| Howzabout a one-liner?  (Though Randal can probably shorten it...)
| 
| # Teaching Uniquify to handle null strings is no big deal, but
| # it sort of spoils the cuteness of the line-liner...
| 
| sub Uniquify{local($prev);grep($_ ne$prev&&($prev = $_),@_);}
| 
| print &Uniquify(split(//,"JJJJusstt   aannothhher   ppperlll haaacker,,,"));

Arggghh!  O(n**2) algorithms are for the birds.  Remembering that the
original request was "sort -u" equivalent, I flip to page 29 of "the
book", and type in:

undef %mark; grep($mark{$_}++,@old); @new = sort keys %mark; undef %mark;

All the goodies in here you won't believe, and we're still typin'em
in.

print "Just another Perl [book] hacker,"
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/