Generator::key

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

    Generator::key — Get the yielded key

    Description

    public Generator::key(): mixed

    Gets the key of the yielded value.

    Parameters

    This function has no parameters.

    Return Values

    Returns the yielded key.

    Examples

    Example #1 Generator::key() example

    <?php

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

    $gen = Gen();

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

    The above example will output:

    key => value

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    User Contributed Notes 1 note

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    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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