IteratorIterator::valid (PHP 5 >= 5.1.0, PHP 7, PHP 8)IteratorIterator::valid — Checks if the current element is valid 说明 public IteratorIterator::valid(): bool Checks whether the current element is valid. 参数 此函数没有参数。 返回值 Returns true if the current element is valid, otherwise false 参见 iterator_count() - 计算迭代器中元素的个数 IteratorIterator::current() - Get the current value