Generator::key

    (PHP 5 >= 5.5.0, PHP 7, PHP 8)

    Generator::key — yield したキーを取得する

    説明

    public Generator::key(): mixed

    yield した値のキーを取得します。

    パラメータ

    この関数にはパラメータはありません。

    戻り値

    yield したキーを返します。

    例

    例1 Generator::key() の例

    <?php

    function Gen()
    {
    yield     'key' => 'value';
    }

    $gen = Gen();

    echo     "{$gen->key()} => {$gen->current()}";

    上の例の出力は以下となります。

    key => value

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    User Contributed Notes 1 note

    up
    1
    jasonrlester at yahoo dot com
    2 years ago
    This is important when considering how other Generators work such as JavaScript's an Python's. While PHP's generator has the ->valid() method they don't, or an equivalent. JS uses Iterator protocol which says next() should return an object of

    {
    done: bool,
    value: mixed
    }

    In which case you can use keys->done to see if the generator can still be iterated.
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