xpath: get nodes that do not have an X ancestor

Question

I want all nodes of an xml document that are not descendants of nodes X.

(My actual problem is a little more complex, but I\'m stuck with the \"are not descendants\" par

Answer 1

If you translate "are not descendants" to "have no ancestor", you get the expression //*[not(ancestor::X)]. This will return all nodes in a document, which are not descendants of nodes named "X".