Re^2: $str to %hash to @ary

Unfortunately, your code doesn't actually work; as written it lumps the last two outputs together, and I see it outputting "6" 60% of the time, and "19" never.

I'll go post my test code elsewhere and you can see if I've somehow miscopied your code.

--
@/=map{[/./g]}qw/.h_nJ Xapou cets krht ele_ r_ra/;
map{y/X_/\n /;print}map{pop@$_}@/for@/
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Comment on Re^2: $str to %hash to @ary Download Code

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Re^3: $str to %hash to @ary by QM (Parson) on Jul 26, 2004 at 01:32 UTC
You're correct. I didn't test the code well, and seem to have gotten several things backward or out of whack. Here's properly tested code (I hope): #!/your/perl/here use strict; use warnings; 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 += $k; $ad_lookup{$count} = $hash{$k}; } my @ad_lookup_sorted_keys = sort {$b <=> $a} keys %ad_lookup; my %seen; for my $rand ( 1..$count ) { # my $rand = rand($count); my $adid; foreach my $key ( @ad_lookup_sorted_keys ) { if ( $rand <= $key ) { $adid = $ad_lookup{$key}; } else { last; } } # print "$adid\n"; $seen{$adid}++; } foreach my $k ( sort {$a <=> $b} keys %seen ) { print "\$seen{$k}: $seen{$k}\n"; } [download] Which outputs: `$seen{6}: 27 $seen{19}: 23 $seen{21}: 33 $seen{43}: 17` [download] [There would be a slight shift going back to `rand`, because of the 0..99 and 1..100 difference. I believe you just need to change: `$ad_lookup{$count} = $hash{$k};` [download] to: `$ad_lookup{$count-1} = $hash{$k};` [download] ] I should note there are several ways to do this and get it right, and this is but one. Also, the key sort is only done once. A binary search on the keyspace would be faster, if there are many keys, but I'd estimate you would need a hundred keys or so to make it worth while. [Feel free to test that if you like] -QM -- Quantum Mechanics: The dreams stuff is made of	[reply] [d/l] [select]

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Re^3: $str to %hash to @ary
by QM (Parson) on Jul 26, 2004 at 01:32 UTC

#!/your/perl/here
use strict;
use warnings;

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 += $k;                        
    $ad_lookup{$count} = $hash{$k};
}                        

my @ad_lookup_sorted_keys = sort {$b <=> $a} keys %ad_lookup;

my %seen;
for my $rand ( 1..$count )
{
#    my $rand = rand($count);    
    my $adid;
    foreach my $key ( @ad_lookup_sorted_keys )
    {
        if ( $rand <= $key )
        {
            $adid = $ad_lookup{$key};
        }
        else
        {
            last;
        }
    }
#    print "$adid\n";
    $seen{$adid}++;
}
foreach my $k ( sort {$a <=> $b} keys %seen )
{
    print "\$seen{$k}: $seen{$k}\n";
}
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$seen{6}: 27
$seen{19}: 23
$seen{21}: 33
$seen{43}: 17
[download]

rand

    $ad_lookup{$count} = $hash{$k};
[download]

    $ad_lookup{$count-1} = $hash{$k};
[download]

I should note there are several ways to do this and get it right, and this is but one. Also, the key sort is only done once. A binary search on the keyspace would be faster, if there are many keys, but I'd estimate you would need a hundred keys or so to make it worth while. [Feel free to test that if you like]

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

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