(PHP 5 >= 5.1.0, PHP 7)
SimpleXMLIterator::key — Return current key
This method gets the XML tag name of the current element.
此函数没有参数。
Returns the XML tag name of the element referenced by the current SimpleXMLIterator object or FALSE
Example #1 Get the current XML tag key
<?php
$xmlIterator = new SimpleXMLIterator('<books><book>PHP basics</book><book>XML basics</book></books>');
echo var_dump($xmlIterator->key());
$xmlIterator->rewind(); // rewind to the first element
echo var_dump($xmlIterator->key());
?>
以上例程会输出：
bool(false) string(4) "book"