MutableVector::firstKey
Returns the first key in the current MutableVector
public function firstKey(): ?int;
Returns
?int- The first key in the currentMutableVector, ornullif the currentMutableVectoris empty.
Returns the first key in the current MutableVector
public function firstKey(): ?int;
?int - The first key in the current MutableVector, or null if the
current MutableVector is empty.