PHPのお勉強！

PHP TOP
PHP 8.4.2 Released!

    Ds\Map::filter

    (PECL ds >= 1.0.0)

    Ds\Map::filter — Creates a new map using a callable to determine which pairs to include

    説明

    public Ds\Map::filter(callable $callback = ?): Ds\Map

    Creates a new map using a callable to determine which pairs to include.

    パラメータ

    callback

    callback(mixed $key, mixed $value): bool

    Optional callable which returns true if the pair should be included, false otherwise.

    If a callback is not provided, only values which are true (see converting to boolean) will be included.

    戻り値

    A new map containing all the pairs for which either the callback returned true, or all values that convert to true if a callback was not provided.

    例

    例1 Ds\Map::filter() example using callback function

    <?php
    $map     = new \Ds\Map(["a", "b", "c", "d", "e"]);

    var_dump($map->filter(function($key, $value) {
    return     $key % 2 == 0;
    }));
    ?>

    上の例の出力は、 たとえば以下のようになります。

    object(Ds\Map)#3 (3) {
  [0]=>
  object(Ds\Pair)#2 (2) {
    ["key"]=>
    int(0)
    ["value"]=>
    string(1) "a"
  }
  [1]=>
  object(Ds\Pair)#4 (2) {
    ["key"]=>
    int(2)
    ["value"]=>
    string(1) "c"
  }
  [2]=>
  object(Ds\Pair)#5 (2) {
    ["key"]=>
    int(4)
    ["value"]=>
    string(1) "e"
  }
}

    例2 Ds\Map::filter() example without a callback function

    <?php
    $map     = new \Ds\Map(["a" => 0, "b" => 1, "c" => true, "d" => false]);

    var_dump($map->filter());
    ?>

    上の例の出力は、 たとえば以下のようになります。

    object(Ds\Map)#2 (3) {
  [0]=>
  int(1)
  [1]=>
  string(1) "a"
  [2]=>
  bool(true)
}

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes

    There are no user contributed notes for this page.
    To Top