c:\@Work\Perl>perl -wMstrict -le
"use constant PATH_ELEMENT => 0;
 ;;
 my @out = (
   [ '+', '',      'before' ],
   [ 'u', 'the',   'the'    ],
   [ 'u', 'quick', 'quick'  ],
   [ 'c', 'brown', 'green'  ],
   [ 'u', 'fox',   'fox'    ],
   );
 my $path = join '', map $_->[PATH_ELEMENT], @out;
 ;;
 $path eq '+uucu' or die qq{bad path: '$path'};
 ;;
 print qq{proper path: '$path'};
"
proper path: '+uucu'
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Update: Please see the constant pragma, and the join, map and die built-ins. (Update: See also the tutorial Map: The Basics and the subsidiary discussion of map in Complex sorting.)