php - Can we use { to declare e variable variable?

I have a piece of code which I a trying to shorten using variable variable, wanted to check if this is a valid code.

Original code:

$town = ( $_POST['town'] ) ;
$county = ($_POST['county'] ) ;

// Update town user meta
if ( !empty( $town ) )
    update_user_meta( $user_id, 'town', $town);

// Delete town user meta
else
    delete_user_meta( $user_id, 'town' );

//Update county user meta
if ( !empty( $county ) )
    update_user_meta( $user_id, 'county', $county);

// Delete county user meta
else
    delete_user_meta( $user_id, 'county' );
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Shortened code :

$fields = array("town","county");
foreach ($fields as $field) {
${$field} = $_POST[$field];
    if ( !empty( $field ) ) { update_user_meta( $user_id, "$field", ${$field}); } else { delete_user_meta( $user_id, "$field" ); }  
}
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Without the shortened code, we can accommodate more variables, which is the goal.

Thanks for your time.

EDIT

Special thanks to all the negative voters. My last post here got 7 negative votes, here its 2 only so far. Com'n guys, break my last record.

On a more serious note, there must be a stricter policy by Stackoverflow about negative voting and there must be a scrutiny on such votes by other people - I feel, random mass negative votes like these can be highly demoralizing.