xmlGetAttr {XML}R Documentation

Get the value of an attribute in an XML node

Description

This is a convenience function that retrieves the value of a named attribute in an XML node, taking care of checking for its existence. It also allows the caller to provide a default value to use as the return value if the attribute is not present.

Usage

xmlGetAttr(node, name, default = NULL, converter = NULL)

Arguments

node the XML node
name the name of the attribute
default a value to use as the default return if the attribute is not present in the XML node.
converter an optional function which if supplied is invoked with the attribute value and the value returned. This can be used to convert the string to an arbitrary value which is useful if it is, for example, a number. This is only called if the attribute exists within the node. In other words, it is not applied to the default value.

Details

This just checks that the attribute list is non-NULL and that there is an element with the specified name.

Value

If the attribute is present, the return value is a string which is the value of the attribute. Otherwise, the value of default is returned.

Author(s)

Duncan Temple Lang

References

http://www.w3.org/XML, http://www.jclark.com/xml, http://www.omegahat.org

See Also

xmlAttrs

Examples

 node <- xmlNode("foo", attrs=c(a="1", b="my name"))

 xmlGetAttr(node, "a")
 xmlGetAttr(node, "doesn't exist", "My own default value")

 xmlGetAttr(node, "b", "Just in case")

[Package XML version 0.97-0 Index]