My guess is:

my $string = "1:1,2:1,3:2,500:2,505:1"; 
my %hash = $string=~/([-.\w]*):([-.\w]*),/g; 
my @array = $string=~/([-.\w]*):/g; 
use Data::Dumper; print Dumper \@array, \%hash;
[download]

Update: that's wrong of course. Here's the corrected one:

my $string = "1:1,2:1,3:2,500:2,505:1"; 
my %hash = $string=~/([-.\w]*):([-.\w]*)/g; 
@array = $string=~/([-.\w]*):/g; 
use Data::Dumper; print Dumper \@array, \%hash;
[download]

Sorry.