Question about XPath with functions in it

Question

this is a follow-up question of my previous thread:

Please help me on understanding this XPath

I have an XPath as:

Answer 1

Your code will result in a number, which will equal:

The position in the Current node list, minus the number of any preceding siblings, minus 18.

Generally speaking, different operators can be combined into expressions as you demonstrate in your example.

A note: Use position() with caution, because sometimes the current node list is not easy to see.