my @copy = $AP_NumClients[0]; for (my $i = 1; $i < @AP_NumClients; $i++) { my $id = $AP_NumClients[$i][0]; if ($id =~ s/\.1$/.0/ && $id eq $copy[-1][0]) { $copy[-1][1] += $AP_NumClients[$i][1] } else { push @copy, $AP_NumClients[$i]; } } @AP_NumClients = @copy;