lxml获得倒数第二个元素

Question

I have a bunch of ul and I want to get the second last li element in each. The number of list items is variable so I cannot do something like

tree.xpath('//ul/li[3]') # if it had four elements

Answer 1

You can use last() function :

tree.xpath('//ul/li[last()-1]')

According to the documentation:

 fn:last() as xs:integer 

Summary: Returns the context size from the dynamic context. (See Section C.2 Dynamic Context ComponentsXP.) If the context item is undefined, an error is raised: [err:XPDY0002]XP.