Count the number of values for a property of a resource
This method will return 0 if the property does not exist.
string $property The name of the property (e.g. foaf:name):
string $type The type of value to filter by (e.g. literal):
string $lang The language to filter by (e.g. en):
integer The number of values associated with the property
public function count($property, $type = null, $lang = null) {
$this
->checkHasGraph();
return $this->graph
->count($this->uri, $property, $type, $lang);
}