use Data::Dumper;

my @array = (a..z);

my %hash = map { $array[$_] => $_ } 0..$#array;

print Dumper(\%hash);

__END__

$VAR1 = {
          'w' => 22,
          'r' => 17,
          'a' => 0,
          'x' => 23,
          'd' => 3,
          'j' => 9,
          'y' => 24,
          'u' => 20,
          'k' => 10,
          'h' => 7,
          'g' => 6,
          'f' => 5,
          't' => 19,
          'i' => 8,
          'e' => 4,
          'n' => 13,
          'v' => 21,
          'm' => 12,
          's' => 18,
          'l' => 11,
          'c' => 2,
          'p' => 15,
          'q' => 16,
          'b' => 1,
          'z' => 25,
          'o' => 14
        };


##</code><code>##

@hash{@array} = 0..$#array;