dr@dns:~$ cat sscce.pl
use strict;
use warnings;
use feature 'say';

my $str = 'a b c d e f ';
my ($key, undef, undef, undef, undef, undef, $val) = split(" ", $str);
say "Val = <$val>";
my ($key2, $val2) = (split(" ", $str))[0,6];
say "Val2 = <$val2>";
dr@dns:~$ perl sscce.pl
Val = <>
Use of uninitialized value $val2 in concatenation (.) or string at sscce.pl line 9.
Val2 = <>