my @quarter = qw(q0
   q3 q3
   q4 q4 q4
   q1 q1 q1 
   q2 q2 q2
   q3);
# Later...
@sorted = sort
    { $quarter[(split(/\//, $a))[0]] cmp
      $quarter[(split(/\//, $b))[0]] }
        @rawdates;