Find duplicates in an array

[Gopal Karunakar]

Hi All,

I needed to find all the duplicate values in an array and their count of
occurences. Any help would be appreciated .

Thanks in advance.

[Thomas Bätzler]

Gopal Karunakar <gk.kali...@gmail.com> asked:

> I needed to find all the duplicate values in an array and their count
> of occurences. Any help would be appreciated .

#!/usr/bin/perl -w

use strict;

my @array=qw(foo baz bar foo baz foo);

my %seen;

foreach my $item (@array){
$seen{$item}++
}

foreach my $item (keys %seen){
print "item $item seen $seen{$item} times.\n"
}

__END__

HTH,
Thomas

[Taylor, Andrew (ASPIRE)]

>I needed to find all the duplicate values in an array and their count
of
>occurences. Any help would be appreciated .

You could use a hash:

use strict;
use warnings;

my @animals = ("cat","dog","wombat","cat","monkey","cat","monkey");
my %howmany;

foreach my $critter (@animals)
{
$howmany{$critter}++;
}

foreach my $key (keys %howmany)
{
print "$key $howmany{$key}\n";
}

If you only want cases with count > 1 then put an if around the print.

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[C.DeRykus]

On Jun 2, 12:37 am, gk.kalipuray...@gmail.com (Gopal Karunakar) wrote:
> Hi All,
>
> I needed to find all the duplicate values in an array and their count of
> occurences. Any help would be appreciated .
>

See: perldoc -q dup
perldoc perlvar

Although even non-dup array members get printed,
Data::Dumper and perl's pre-defined @ARGV can
be handy. Just pass the actual array members to
perl as command line arguments:

perl -MData::Dumper -e '$seen{$_}++ for @ARGV;
print Dumper \%seen'
foo bar bat foo

--
Charles DeRykus