xpath_nodeset
xpath_nodeset (arr, expr[, doc])
This function evaluates an XPath expression with respect to a document and returns the result as an array of OIDs. This function can be used to identify a group of elements to be iterated through. It can also be used for navigation, for example, by passing one of the returned OIDs to goto_oid.
• arr — An unordered array of OIDs returned by expr.
• expr — A valid XPath expression that evaluates to a node set containing only XPath nodes that have associated OIDs.
Do not use expressions that contain position() or last(). They do not work in this context. Use the preceding-sibling or following-sibling axes instead to achieve the desired results. For example:
◦ count(preceding-sibling::*)=0 will test that the context node is the first child of its parent.
◦ count(preceding-sibling::para)=1 will test that the context node is the second para child of its parent.
◦ count(following-sibling::*)=0 is a viable alternative to position()=last()
• doc — The identifier of the document tree to use as the context node. If omitted or 0, the current document is used.
This function fills the array
arr with the first OID of each XPath node returned by
expr. The return value is the number of OIDs stored in
arr. Duplicate OIDs may be returned if more than one XPath node resolves to the same OID.
oid_null is returned for any XPath node that cannot be converted to an OID (for example, namespace nodes and attributes).
To handle errors, call this function from within a catch.
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