Count duplicates in array.

RuneK has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Count duplicates in array. by rdfield (Priest) on Nov 18, 2002 at 12:03 UTC
Use a hash.... `my %hash; $hash{$_}++ foreach (@array); print "$_: $hash{$_} " foreach (sort {$hash{$a} <=> $hash{$b}} keys %h +ash);` [download] I'd have looked up a reference or two, but it's quicker to type in the code :) rdfield	[reply] [d/l]
Re: Count duplicates in array. by BrowserUk (Patriarch) on Nov 18, 2002 at 12:30 UTC
Or `#! perl -slw use strict; my @array = ('bent', 'svend', 'gert','pete','svend','pete'); my ($temp, $count) = ("@array", 0); ($count = $temp =~ s/($_)//g) and printf "%2d:%s\n", $count, $_ for @a +rray; __END__ c:\test>213719 1:bent 2:svend 1:gert 2:pete c:\test>` [download] Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color. Pick up your cloud down the end and "Yes" if you get allocated a grey one they *are* a bit damp under foot, but someone has to get them. Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory. Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.	[reply] [d/l]
Re^2: Count duplicates in array. by ravi45722 (Pilgrim) on Sep 08, 2015 at 05:54 UTC
It's working but i have some other need. My array is like this. `@array=('SMSC_absentsubscriberSM','SMSC_absentsubscriberSM_SC_1','SMSC +_absentsubscriberSM_SC_2','SMSC_absentsubscriberSM',....and so on);` [download] Please suggest me to find exact duplicate in the array. Thanking you	[reply] [d/l]
Re: Count duplicates in array. by RMGir (Prior) on Nov 18, 2002 at 12:50 UTC
It's rare that I think of a solution to a perl problem that DOESN'T involve regexes, hashes, or odd data structures: `#!/usr/bin/perl -w use strict; my @array=('bent','svend','gert','pete','svend','pete'); my $prev=""; my $count=0; foreach(sort @array) { if($prev ne $_) { if($count) { printf("%s:%d ",$prev,$count); } $prev=$_; $count=0; } $count++; } printf("%s:%d\n",$prev,$count) if $count;` [download] Obviously, it could be golfed down somewhat, but I wanted to go for the clearer version. The output isn't in the exact order that RuneK specified, but I'm not sure if that's important or not. -- Mike	[reply] [d/l]
Re: Re: Count duplicates in array. by RuneK (Sexton) on Nov 18, 2002 at 12:55 UTC
Thanks for the many answers. It worked just fine. Br, Rune	[reply]
Re: Count duplicates in array. by UnderMine (Friar) on Nov 18, 2002 at 12:13 UTC
First quick and dirty solution `@array = ('bent', 'svend', 'gert','pete','svend','pete'); map($hash{$_}++, @array); print join(' ',map($_.':'.$hash{$_}, sort {$hash{$a}<=>$hash{$b}} keys + %hash));` [download] Hope it helps UnderMine	[reply] [d/l]