AddAllKeysOf - Hhvm — ContextQMD

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Adds the keys of the specified container to the current Set as new values

Hack

public function addAllKeysOf(
  ?KeyedContainer<Tv, mixed> $container,
): Set<Tv>;

Future changes made to the current Set ARE reflected in the returned Set, and vice-versa.

Parameters

?KeyedContainer<Tv,mixed> $container - The container with the new keys to add.

Returns

Set<Tv> - Returns itself.

Examples

This example adds string keys from a Map to a Set as its values:

string-keys.hack

$fruit_calories = Map {
  'apple' => 95,
  'orange' => 45,
};

$vegetable_calories = darray[
  'cabbage' => 176,
  'potato' => 163,
];

$food_names = Set {};

// Add the keys from a Map
$food_names->addAllKeysOf($fruit_calories);

// Add the keys from an associative array
$food_names->addAllKeysOf($vegetable_calories);

\var_dump($food_names);

This example adds int keys from a Map to a Set as its values:

int-keys.hack

$uploaders_by_id = Map {
  4993063 => 'Amy Smith',
  9361760 => 'John Doe',
};

$commenters_by_id = darray[
  4993063 => 'Amy Smith',
  7424854 => 'Jane Roe',
  5740542 => 'Joe Bloggs',
];

$all_ids = Set {};

// Add the keys from a Map
$all_ids->addAllKeysOf($uploaders_by_id);

// Add the keys from an associative array
$all_ids->addAllKeysOf($commenters_by_id);

\var_dump($all_ids);