HH\Pair::keys
Returns an ImmVector with the values being the keys of the current
Pair
public function keys(): ImmVector<int>;
This method will return an ImmVector with keys 0 and 1, and values 0 and
1, since the keys of a Pair are 0 and 1.
Returns
ImmVector<int>- anImmVectorcontaining the integer keys of the currentPairas values.
Examples
$p = Pair {'foo', -1.5};
\var_dump($p->keys());