Returns a Map containing the values of the current Map that meet a supplied condition applied to its keys and values

public function filterWithKey(
  (function(Tk,Tv):bool) $callback,
):     Map<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 mapWithKey().

The keys associated with the current Map remain unchanged in the returned Map; the keys will be used in the filtering process only.


  • (function(Tk,Tv):bool) $callback - The callback containing the condition to apply to the current Map keys and values.

Return Values

  • Map<Tk, Tv> - a Map containing the values after a user-specified condition is applied to the keys and values of the current Map.