#! /usr/perl/bin use warnings; use strict; use Data::Dumper; use warnings; use strict; my @charges = qw/ch1 ch2 ch3 ch4 ch5 ch6 ch7 ch8 ch1 ch2 ch3 ch4 ch5 ch1 ch2 ch6 ch7 ch4 ch3 ch9 ch2 ch4/; my %bundle1 = map { $_ => 0 } qw(ch3 ch4 ch6); my $i; for (@charges) { if (exists $bundle1{$_}) { $i++; if ($i == 3){ print "chx "; $i = 0; } } else { print "$_ "; } } print "\n"; __END__ ch1 ch2 ch5 chx ch7 ch8 ch1 ch2 ch5 ch1 ch2 chx ch7 ch9 ch2 chx