zip

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.

Returns a Map where each value is a Pair that combines the value of the current Map and the provided Traversable

public function zip<Tu>(
  Traversable<Tu> $traversable,
): Map<Tk, Pair<Tv, Tu>>;

If the number of values of the current Map are not equal to the number of elements in the Traversable, then only the combined elements up to and including the final element of the one with the least number of elements is included.

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

Parameters

• Traversable<Tu>$traversable - The Traversable to use to combine with the elements of the current Map.

Returns

• Map<Tk,Pair<Tv, Tu>> - The Map that combines the values of the current Map with the provided Traversable.

Examples

This example shows how zip combines the values of the Map and another Traversable. The resulting Map $labeled_colors has three elements because $labels doesn't have a fourth element to pair with $m.

$m = Map {
  'red' => '#ff0000',
  'green' => '#00ff00',
  'blue' => '#0000ff',
  'yellow' => '#ffff00',
  'purple' => '#663399',
};

$labels = Vector {'My Favorite', 'My 2nd Favorite', 'My 3rd Favorite'};
$labeled_colors = $m->zip($labels);

\var_dump($labeled_colors->count()); // 3

foreach ($labeled_colors as $color => $pair) {
  $hex_code = $pair[0];
  $label = $pair[1];
  echo "{$label}: {$color} ($hex_code)\n";
}