RosettaCodeData/Task/Probabilistic-choice/Perl/probabilistic-choice.pl

39 lines
817 B
Perl

use List::Util qw(first sum);
use constant TRIALS => 1e6;
sub prob_choice_picker {
my %options = @_;
my ($n, @a) = 0;
while (my ($k,$v) = each %options) {
$n += $v;
push @a, [$n, $k];
}
return sub {
my $r = rand;
( first {$r <= $_->[0]} @a )->[1];
};
}
my %ps =
(aleph => 1/5,
beth => 1/6,
gimel => 1/7,
daleth => 1/8,
he => 1/9,
waw => 1/10,
zayin => 1/11);
$ps{heth} = 1 - sum values %ps;
my $picker = prob_choice_picker %ps;
my %results;
for (my $n = 0 ; $n < TRIALS ; ++$n) {
++$results{$picker->()};
}
print "Event Occurred Expected Difference\n";
foreach (sort {$results{$b} <=> $results{$a}} keys %results) {
printf "%-6s %f %f %f\n",
$_, $results{$_}/TRIALS, $ps{$_},
abs($results{$_}/TRIALS - $ps{$_});
}