bigtiny: I think the point you are missing is that the output of the  Dumper function is already a string. As such, it can be operated with or operated on (or passed as a parameter to a function) just as any other string can be.

>perl -wMstrict -le
"use Data::Dumper;
 my @ra = (1, 2, { 3 => 'three' } );
 my $du = Dumper \@ra;
 print qq{**$du**};
"
**$VAR1 = [
          1,
          2,
          {
            '3' => 'three'
          }
        ];
**
[download]

Update: Changed wording, example code slightly to better make the point.