XPath and namespace specification for XML documents with an explicit default namespace

Question

I\'m struggling to get the correct combination of an XPath expression and the namespace specification as required by package XML (argument namespaces) f

Answer 1

I had a similar issue, but in my case I did not care about the namespace and would like a solution that ignored the namespace.

Assume that we have the following XML in the variable myxml:

Test

In R we want to read this so we run:

myxml <- '

  Test


'
myxmltop <- xmlParse(myxml)
ns <- xmlNamespaceDefinitions(myxmltop, simplify =  TRUE)

Here I have simplified Rappster's code by using the simplify=TRUE parameter. Now we can add the name/prefix of the namespace as in Rappster's code:

names(ns)[1] <- "xmlns"

Now we can refer to this namespace by:

getNodeSet(myxmltop, "//xmlns:Parameter", namespaces =ns)

Simpler solution (ignoring namespaces)

We can also be more flexible by matching on any namespace by doing:

myxmltop <- xmlParse(myxml)
getNodeSet(myxmltop, "//*[local-name() = 'Parameter']")

This solution was inspired by this SO answer.