(PHP 5, PHP 7, PHP 8)
Iterator::key — Return the key of the current element
abstract public Iterator::key ( ) : scalar
Returns the key of the current element.
This function has no parameters.
Returns scalar on success, or null on failure.
Issues E_NOTICE on failure.
© 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/iterator.key.php