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Convert an XML node/document to a more R-like list

xmlToList.Rd

This function is an early and simple approach to converting an XML node or document into a more typical R list containing the data values directly (rather than as XML nodes). It is useful for dealing with data that is returned from REST requests or other Web queries or generally when parsing XML and wanting to be able to access the content as elements in a list indexed by the name of the node. For example, if given a node of the form <x> <a>text</a> <b foo="1"/> <c bar="me"> <d>a phrase</d> </c> </x> We would end up with a list with elements named "a", "b" and "c". "a" would be the string "text", b would contain the named character vector c(foo = "1") (i.e. the attributes) and "c" would contain the list with two elements named "d" and ".attrs". The element corresponding to "d" is a character vector with the single element "a phrase". The ".attrs" element of the list is the character vector of attributes from the node <c>...</c>.

Usage

xmlToList(node, addAttributes = TRUE, simplify = FALSE)

Arguments

node

the XML node or document to be converted to an R list. This can be an "internal" or C-level node (i.e. XMLInternalNode-class) or a regular R-level node (either XMLNode-class or XMLHashNode).

addAttributes

a logical value which controls whether the attributes of an empty node are added to the

simplify

a logical value that controls whether we collapse the list to a vector if the elements all have a common compatible type. Basically, this controls whether we use sapply or lapply.

Value

A list whose elements correspond to the children of the top-level nodes.

Author

Duncan Temple Lang

See also

xmlTreeParse getNodeSet and xpathApply xmlRoot, xmlChildren, xmlApply, [[, etc. for accessing the content of XML nodes.

Examples

tt = 
 '<x>
     <a>text</a>
     <b foo="1"/>
     <c bar="me">
        <d>a phrase</d>
     </c>
  </x>'

  doc = xmlParse(tt)
  xmlToList(doc)
#> $a
#> [1] "text"
#> 
#> $b
#> foo 
#> "1" 
#> 
#> $c
#> $c$d
#> [1] "a phrase"
#> 
#> $c$.attrs
#>  bar 
#> "me" 
#> 
#> 

   # use an R-level node representation
  doc = xmlTreeParse(tt)
  xmlToList(doc)
#> $a
#> [1] "text"
#> 
#> $b
#> foo 
#> "1" 
#> 
#> $c
#> $c$d
#> [1] "a phrase"
#> 
#> $c$.attrs
#>  bar 
#> "me" 
#> 
#>