问题
How do I select the globally-last text node using xpath? I tried this, but it gives me the last node in every context of the document.
lxml.html.fromstring('1<a>2<b>3</b>4<c>5</c>6</a>').xpath('//text()[last()]')
['1', '3', '5', '6']
I can do this, but it's inefficient in both time and space, especially as the document gets large.
lxml.html.fromstring('1<a>2<b>3</b>4<c>5</c>6</a>').xpath('//text()[last()]')[-1]
'6'
I tried to use an index of -1, but that gives me an empty list. I tried to use some of the reverse axes (so that I could index with 1), but I couldn't get them to work in a global context.
回答1:
Use:
(//text())[last()]
This is a FAQ.
Explanation:
The XPath pseudo-operator // has a lower precedence (priority), than the [] operator, which binds stronger to the node-test preceding it.
As in Math and in every language, the way to override default priority is by using brackets.
来源：https://stackoverflow.com/questions/10098593/xpath-how-do-we-select-just-the-very-last-text-node