my @employees; # Defined elsewhere
for (@employees) {
    $_->salary(    $_->salary() * 1.02 );
    $_->frobnitz(  $_->frobnitz + 1.5  );
}

# Or if you want to keep closer to the old code and 
# live with O(2n) . . . 
$_->salary(    $_->salary() * 1.02 ) for @employees;
$_->frobnitz(  $_->frobnitz + 1.5  ) for @employees;