@new_hashes = map{ my $x = $_; +{ map { $_=>$x->{$_} } @wanted_keys } } @old_hashes;

##</code><code>##

@new_hashes = map { my %x; @x{@wanted_keys}=@$_{@wanted_keys}; \%x } @old_hashes; # untested

##</code><code>##

@cols = (split(' ', $data, 4),
         (map scalar reverse, reverse split(' ', reverse($data), 4))[1..3]);

##</code><code>##

@cols = split(' ', $data, 4);
@cols[7,6,5,4,3] = map scalar reverse, split ' ', reverse($cols[3]), 5;

##</code><code>##

@cols = ((split(' ', $data, 4))[0..2], reverse map scalar reverse, split ' ', reverse((split ' ', $data, 4)[-1]), 5);