use strict;
use warnings;
use Data::Dumper;

my $string = "RABBIT 45 -126.06686";
my @parts = split /\s+/, $string;
print Dumper(\@parts);

__END__

$VAR1 = [
          'RABBIT',
          '45',
          '-126.06686'
        ];
[download]

Also, the code you posted has a compile error.

Which part of your code should extract -126.06686 from your string?

Also read perlretut and perlre.

Once again, your questions belong in the Seekers of Perl Wisdom section, not PerlMonks Discussion. So you should be posting here.

Edit: BTW, your code doesn't even compile, so either you did not actually try, or you are not showing us your real test.

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1193292

use strict;
use warnings;

while(<DATA>)
  {
  my $n = 1;
  s/(?<!\S)(?=\S)/ $n++ . ')' /ge;
  print;
  }

__DATA__
RABBIT 45 -126.06686
[download]

"Read Where should I post X? if you're not absolutely sure you're posting in the right place."

This is displayed every time you post, you keep ignoring this and requests to post in the appropriate section of the site.