my @arr1;
@arr1 = map { push @arr1, ($_+ 2) } @data;

##</code><code>##

my @dataPlus2 = map { my $bullshit = 'XYZ'; #see below
                      $_ + 2
                    }@data;

##</code><code>##

foreach my $root (map { sqrt($_) }@data)
{
   #do something with this square root...
}