XML (version 3.1-1)

addChildren: Add child nodes to an XML node

Description

This collection of functions allow us to add, remove and replace children from an XML node and also to and and remove attributes on an XML node. These are generic functions that work on both internal C-level XMLInternalElementNode objects and regular R-level XMLNode objects.

addChildren is similar to addNode and the two may be consolidated into a single generic function and methods in the future.

Usage

addChildren(node, ..., kids = list(...), at = NA, cdata = FALSE)
removeChildren(node, ..., kids = list(...), free = FALSE)
removeNodes(node, free = rep(FALSE, length(node)))
replaceNodes(oldNode, newNode, ...)
addAttributes(node, ..., .attrs = NULL, 
               suppressNamespaceWarning = getOption("suppressXMLNamespaceWarning", FALSE),
                append = TRUE)
removeAttributes(node, ..., .attrs = NULL, .namespace = FALSE,
                  .all = (length(list(...)) + length(.attrs)) == 0)

Value

• Each of these functions returns the modified node. For an internal node, this is the same R object and only the C-level data structures have changed. For an R XMLNode object, this is is an entirely separate object from the original node. It must be inserted back into its parent "node" or context if the changes are to be seen in that wider context.

concept

• XML
• document tree

References

libxml2 http://www.xmlsoft.org

See Also

xmlTree newXMLNode

Examples

b = newXMLNode("bob", namespace = c(r = "http://www.r-project.org", omg = "http://www.omegahat.org"))

cat(saveXML(b), "")

addAttributes(b, a = 1, b = "xyz", "r:version" = "2.4.1", "omg:len" = 3)
cat(saveXML(b), "")

removeAttributes(b, "a", "r:version")
cat(saveXML(b), "")


removeAttributes(b, .attrs = names(xmlAttrs(b)))


addChildren(b, newXMLNode("el", "Red", "Blue", "Green",
                           attrs = c(lang ="en")))

k = lapply(letters, newXMLNode)
addChildren(b, kids = k)

cat(saveXML(b), "")

removeChildren(b, "a", "b", "c", "z")

  # can mix numbers and names
removeChildren(b, 2, "e")  # d and e

cat(saveXML(b), "")


i = xmlChildren(b)[[5]]
xmlName(i)

 # have the identifiers
removeChildren(b, kids = c("m", "n", "q"))



x <- xmlNode("a", 
               xmlNode("b", "1"),
               xmlNode("c", "1"),
	       "some basic text")

v = removeChildren(x, "b")

  # remove c and b
v = removeChildren(x, "c", "b")

  # remove the text and "c" leaving just b
v = removeChildren(x, 3, "c")

# this won't work as the 10 gets coerced to a 
    # character vector element to be combined with 'w'
    # and there is no node name 10.
 removeChildren(b, kids = c(10, "w"))


 # for R-level nodes (not internal)

z = xmlNode("arg", attrs = c(default="TRUE"),
              xmlNode("name", "foo"), xmlNode("defaultValue","1:10"))

o = addChildren(z,
                "some text",
                xmlNode("a", "a link", attrs = c(href = "http://www.omegahat.org/RSXML")))
o