xclass {AffyCompatible} | R Documentation |
This function takes an xml object, created from readXml
,
and an xpath query referencing an element of the document,and returns
an R object represneting the element.
The xpath query must retrive an element, not an attribute.
xclass(doc, xpathq, prefix = character(0))
doc |
An XMLInternalDocument retrieved using
readXml . |
xpathq |
A length-1 character string representing an xpath query into the document. |
prefix |
A prefix used to map, when necessary, between the XML
class name and the corresponding R class. For NetAffx -based
classes, the prefix is ‘Affx’; no prefix is required for DTT
or ARR documents. |
An R object corresponding to the class(es) referenced by the xpath query.
Martin Morgan
http://www.w3.org/TR/xpath provides a very useful description of xpath. Addiitonal references are in the vignette `Retrieving MAGE and ARR sample attributes'.
The vignettes `Retrieving MAGE and ARR sample attributes' and `Annotation retrieval with NetAffxResource' for detailed illustration of use.
readXml
for appropriately reading XML documents.
example(readXml)