johnnywang has asked for the wisdom of the Perl Monks concerning the following question:

This must be well-known, but I can't seem to find a good answer: given a range and size, what's the best way to find a set of distinct random numbers? i.e.
sub distinct_random_int{ my($num, $start,$end) = @_; #return an arry of size $num }
Updated: changed "different" to "distinct" after Aristotle's remark.