#!/usr/bin/perl -l

# http://perlmonks.org/?node_id=1169780

use strict;
use warnings;

my @allele = <DATA>;
my @newcounts;
$_ = join '', @allele;

push @newcounts, $& =~ tr/\n// while /^(.*\n)\1*/gm;
print for @newcounts;

__DATA__
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*03:01 
HLA-A*03:01 
HLA-A*03:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:01 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03 
HLA-A*02:03

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In reply to Re: Count non unique groups of elements in an array by Anonymous Monk
in thread Count non unique groups of elements in an array by Sandy_Bio_Perl

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