>perl -wMstrict -lE
"BEGIN {
   eval qq{sub $_ () { $_ }} for qw(ODDS EVENS FIVERS);
   }
 ;;
 my %parts;
 for my $n (0 .. 20) {
   push
     @{ $parts{ $n % 5 == 0 ? FIVERS : $n % 2 == 0 ? EVENS : ODDS } },
     $n;
   }
 ;;
 say qq{'@{$parts{ODDS}}'};
 say qq{'@{$parts{FIVERS}}[1 .. 3]'};
 say qq{'@{$parts{EVENS}}'};
"
'1 3 7 9 11 13 17 19'
'5 10 15'
'2 4 6 8 12 14 16 18'