On 2014-03-05 08:32, Alex McHugh wrote:
> This is somewhat of a pure xpath question.
>
> I'm trying to perform a set operation on value identity.
>
> Variable A is composed of text nodes
> Variable B is composed of attributes (all with the same attribute name,
> only the attribute value differs)
>
> The following xpath expression gives me the text nodes in common (value
> intersection)
> $A[. = $B]
>
> However what I want is the text nodes with values that are unique to
> variable A.
>
> $A[not(. = $B)]
>
> Gives me an empty nodeset. I had expected this to work. Google seems to
> agree that this is the correct expression. Is there something special about
> attribute nodes?
>
> Any ideas?
>
>

I have used $A[not(. = $B)] many times and it works fine.
Are both $A and $B nodesets?
Give us an example on how the structure differs between A & B.