#!/usr/bin/perl

use strict;
use warnings;

my @array = qw(a123 abc abc1 123a 123_1 abc_1);

for my $element (@array){
  print "before: $element\n";
  $element++;
  print "after: $element\n";
  print "\n";
}

__DATA__

output (with comments)

# these "do what you want"

before: a123
after: a124

before: abc
after: abd

before: abc1
after: abc2

# and these don't :-(

# if the string starts with a number
# Perl treats it as number

before: 123a
after: 124

# the _ always breaks the magic

before: 123_1
after: 124

# not at all sure what's happening here!

before: abc_1
after: 1