ConstMap containing the values of the current
meet a supplied condition applied to its keys and values
public function filterWithKey( (function(Tk, Tv): bool) $fn, ): ConstMap<Tk, Tv>;
Only keys and values that meet a certain criteria are affected by a call to
filterWithKey(), while all values are affected by a call to
The keys associated with the current
ConstMap remain unchanged in the
ConstMap; the keys will be used in the filtering process only.
(function(Tk, Tv): bool) $fn- The callback containing the condition to apply to the current
ConstMapkeys and values.
ConstMap<Tk, Tv>- a
ConstMapcontaining the values after a user-specified condition is applied to the keys and values of the current