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

down

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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