Re: Get All Duplicated Elements in an Array (Once, without shifting)

Maybe I'm missing something, but...

for(@in){
   $hash{$_}++;
}
foreach my $key (keys %hash){
   print "$key is lonely\n" if ($hash{$key} == 1);
   print "$key has friends\n" if ($hash{$key} != 1);
}
[download]

thor

Update: changed %hash{$_}++ to $hash{$_}++ to make it correct.

Comment on Re: Get All Duplicated Elements in an Array (Once, without shifting) Download Code

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•Re: Re: Get All Duplicated Elements in an Array (Once, without shifting) by merlyn (Sage) on Oct 15, 2002 at 01:14 UTC
Well, the one thing you're missing is that `%hash{$_}++` is illegal syntax, unless you've already projected forward about three years and are using Perl 6. -- Randal L. Schwartz, Perl hacker	[reply]
Re: •Re: Re: Get All Duplicated Elements in an Array (Once, without shifting) by demerphq (Chancellor) on Oct 18, 2002 at 17:35 UTC
While it is true that `%hash{$_}++` is illegal syntax, it is interesting to note that `%hash->{$_}++`is not. (But it only works on actual hashes and not hash references.) AFAIK its a bug, but one that has basically become a feature. `use Data::Dumper; use strict; use warnings; my %hash; %hash->{$_}=$_ foreach 0..5; print Dumper(\%hash); __END__ $VAR1 = { '0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5 };` [download] It embarrassed the crap out of me when I discovered this. I was reviewing some code of my colleagues, (relatively new to perl at the time) and identified these as compile time errors. He politely told me what I was full of :-) and then showed me it compiled (and worked) fine. Luckily he had a few other subtle bugs that I found so I managed to avoid looking like a complete moron. :-) --- demerphq my friends call me, usually because I'm late....	[reply] [d/l] [select]
Re^4: Get All Duplicated Elements in an Array (Once, without shifting) by dragonchild (Archbishop) on Apr 18, 2005 at 14:20 UTC
This syntax has been deprecated as of 5.8. (q.v. http://perldoc.perl.org/perl58delta.html#Deprecations.) It also has issues under other versions with an attempt to free an unreferenced scalar. Looks cool, though. My wife's blog	[reply]
Re^3: Get All Duplicated Elements in an Array (Once, without shifting) by graq (Curate) on Aug 11, 2006 at 13:43 UTC
How much of an estimate is 'about' and are you still confident with your prediction? :P -=( Graq )=-	[reply]
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