original_string: public static function splitKey($key)
      {
          if (strpos($key, self::FIELD_KEY_SEPARATOR) === false) {
              return null;
          }
          list($sub, $fieldId) = explode(self::FIELD_KEY_SEPARATOR, $key, 2);
  
          return array('sub' => $sub, 'gtf_id_field' => $fieldId);
      }
code: public static function splitKey($key)
      {
          if (strpos($key, self::FIELD_KEY_SEPARATOR) === false) {
              return null;
          }
          list($sub, $fieldId) = explode(self::FIELD_KEY_SEPARATOR, $key, 2);
  
          return array('sub' => $sub, 'gtf_id_field' => $fieldId);
      }
code_tokens: public static function splitKey ( $ key ) { if ( strpos ( $ key , self :: FIELD_KEY_SEPARATOR ) === false ) { return null ; } list ( $ sub , $ fieldId ) = explode ( self :: FIELD_KEY_SEPARATOR , $ key , 2 ) ; return array ( 'sub' => $ sub , 'gtf_id_field' => $ fieldId ) ; }
docstring: Split an external field key in component parts
  
  @param string $sub
  @param int $fieldId
  @return array 'sub' => suIdb, 'gtf_id_field; => fieldId
docstring_tokens: Split an external field key in component parts