my @sorted = sort byPrefix @s;



# sort the keys numerically
sub byPrefix {

# make copies so originals are preserved
  my ( $x, $y ) = ( $a, $b );

# get prefixes
  $x =~ s/:.+//;
  $y =~ s/:.+//;

# RV
  $_=0;
  $x < $y && $_--;
  $x > $y && $_++;
  $_;
}