HH\ImmMap::filterWithKey

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

Description

public function filterWithKey(
  (function(Tk,Tv):bool) $callback,
): ImmMap<Tk,Tv>

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

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 ImmMap remain unchanged in the returned ImmMap; the keys will be used in the filtering process only.

Parameters

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

Return Values

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

Examples

See Map::filterWithKey for usage examples.