perl -MData::Dumper -e '
%hash = (a => 3, b=> 4, c=>1 ,d=>7); 
@sel = qw(b c); 
@nhash{@sel} = @hash{@sel}; 
print Dumper \%hash;'

##</code><code>##

$VAR1 = {
          'a' => 3,
          'd' => 7
        };