HH\Lib\Vec\filter

Returns a new vec containing only the values for which the given predicate returns true

namespace HH\Lib\Vec;

function filter<Tv>(
  Traversable<Tv> $traversable,
  ?(function(Tv): bool) $value_predicate = NULL,
): vec<Tv>;

The default predicate is casting the value to boolean.

• To remove null values in a typechecker-visible way, see Vec\filter_nulls().
• To use an async predicate, see Vec\filter_async().

Time complexity: O(n * p), where p is the complexity of $value_predicate Space complexity: O(n)

Parameters

• Traversable<Tv>$traversable
• ?(function(Tv): bool) $value_predicate = NULL

Returns

• vec<Tv>

Examples

$numbers = vec[1, 2, 3, 4, 5];
$filter_numbers = Vec\filter($numbers, $number ==> $number % 2 === 0);
echo "Filter numbers are: \n";
\print_r($filter_numbers);
//Output: Filter numbers are:
//vec[2, 4]