n.firstpos(): the set of XML nodes that match the first element of an XPath rooted at node n

firstpos() ：与根在节点n 上的XPath的第一个元素匹配的XML节点集

youdao

n.firstpos(): the set of XML nodes that match the first element of an XPath rooted at node n

firstpos() ：与根在节点n 上的XPath的第一个元素匹配的XML节点集

youdao