How do you identify duplicate values in a numerical sequence using XPath 2.0?

Question

I have an XPath expression which provides me a sequence of values like the one below:

1 2 2 3 4 5 5 6 7

It is easy to convert this to a set of u

Answer 1

Calculate the difference between your original set and the set of distinct values. This is the set of numbers that occur more than once. Note that numbers in this result set are not necessarily distinct if they occur more than twice in the original sequence so convert again to a set of distinct values if this is required.