c:\@Work\Perl\monks>perl -wMstrict -le
"my %formats = ( 1 => ' %s  ',  2 => ' %s ',  3 => ' %s',  4 => '%s', );
 ;;
 for my $x ('a', 'bc', 'def', 'ghij', 'klmno') {
   printf qq{'@{[ $formats{length($x)} // '%4.4s' ]}' \n}, $x;
   }
"
' a  '
' bc '
' def'
'ghij'
'klmn'