ConstMap::filter

Returns a ConstMap containing the values of the current ConstMap that meet a supplied condition.

Description

public function filter(
  (function(Tv):bool) $fn,
): ConstMap<Tk,Tv>

Returns a ConstMap containing the values of the current ConstMap that meet a supplied condition.

Only values that meet a certain criteria are affected by a call to filter(), while all values are affected by a call to map().

The keys associated with the current ConstMap remain unchanged in the returned ConstMap.

Parameters

  • (function(Tv):bool) $fn - The callback containing the condition to apply to the current ConstMap values.

Return Values

  • ConstMap<Tk,Tv> - a Map containing the values after a user-specified condition is applied.