On: Regular Expression That Checks If A Number Is Prim...

[bigiain]

Wasn't at an interview, but I remember quizzing the "new guy" Perl dev with "So explain what this one does":

  @sorted = map  { $_->[0] }
           sort { $a->[1] cmp $b->[1] }
           map  { [$_, foo($_)] }
                @unsorted;

(Twenty years or so back, I could occasionally be "that asshole"... I'm better now, honest...)