PHP-Warning: array_map(): Argument #2 should be an array

Question

I have this Code for fetch data from MySql database:

   $sql = 'SELECT id,title,seotitle FROM ' . PROPERTIES_TABLE  . ' WHERE featured = "A" AND approved = 1 AND id = "' . safe($_GET['id']) . '" LIMIT 1';
   $r = $db->query ( $sql ) or error ('Critical Error' , mysql_error());
   $f = $db->fetcharray( $r );
  // Make all values in the array 'n/a' if empty
   $f = array_map ( 'if_empty', $f);  

if_empty is:

function if_empty ( $value ) 

 { 

  if ($value == '' || $value == '0') 
   return ''; 
  else 
   return $value; 

 }

Now, I see this error:

Warning: array_map(): Argument #2 should be an array in C:\xampp\htdocs\cms\qrcode.php on line 26

how can i fix this ?

Answer 1

Try:

if(is_array($f))   {
   $f = array_map ( 'if_empty', $f);
}

Answer 2

Try:

if ($f) {
    $f = array_map ( 'if_empty', $f);
}