At the expense of making the lookup a little slower: 
my $str="17:43:33:21:23:19:27:6";      
my %hash=split/:/,$str;                
my $count;
my %ad_lookup;
foreach my $k(keys %hash)              
{              
    $count += $hash{$k};                        
    $ad_lookup{$count} = $k;
}                        
my $rand = rand(100);    
my $adid;
foreach ( sort {$a <=> $b} keys %ad_lookup )
{
    $adid = $ad_lookup{$_} unless defined( $adid);
    if ( $_ <= $rand )
    {
        $adid = $ad_lookup{$_};
    }
    else
    {
        last;
    }
}

[download]
Of course, if you want the lookup to be faster, use a binary search instead.

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to Re: $str to %hash to @ary by QM
in thread $str to %hash to @ary by abaxaba

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