Iterator::key

(PHP 5, PHP 7, PHP 8)

Iterator::key — Return the key of the current element

Description

public Iterator::key(): mixed

Returns the key of the current element.

Parameters

This function has no parameters.

Return Values

Returns scalar on success, or null on failure.

Errors/Exceptions

Issues E_NOTICE on failure.

Found A Problem?

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

＋add a note

User Contributed Notes 3 notes

down

michaelgranados at gmail dot com ¶

11 years ago

Since PHP 5.5.X foreach can accept non scalar items. So the return can be anything ;)

down

-2

sofe2038 at gmail dot com ¶

4 years ago

This function may return any type, not just scalar, for some Iterator types. In particular, it is very trivial to write a generator function that yields arbitrary keys:

<?php
function foo() {
  yield null => 1;
  yield new stdclass => 2;
}
?>

down

-3

Lszl Lajos Jnszky ¶

13 years ago

And converts everything to integer except string, so in php the post process could be:

    public function key() {
        $yourKey = $this->createYourKey();
        if (is_object($yourKey) || is_array($yourKey))
            throw new Exception('Array and Object not allowed.');
        elseif (is_string($yourKey))
            return $yourKey;
        else
            return (int) $yourKey;
    }

＋add a note