xmlSubset: Convenience accessors for the children of XMLNode objects.

In XML: Tools for Parsing and Generating XML Within R and S-Plus

Convenience accessors for the children of XMLNode objects.

Description

These provide a simplified syntax for extracting the children of an XML node.

Usage

## S3 method for class 'XMLNode'
x[..., all = FALSE]
## S3 method for class 'XMLNode'
x[[...]]
## S3 method for class 'XMLDocumentContent'
x[[...]]

Arguments

x	the XML node or the top-level document content in which the children are to be accessed. The XMLDocumentContent is the container for the top-level node that also contains information such as the URI/filename and XML version. This accessor method is merely a convenience to get access to children of the top-level node.
...	the identifiers for the children to be retrieved, given as integer indices, names, etc. in the usual format for the generic link{[} and link{[[} operators
all	logical value. When ... is a character vector, a value of TRUE for all means to retrieve all of the nodes with those names rather than just the first one. FALSE gives the usual result of subsetting a list by name which gives just the first element. This allows us to avoid the idiom node[ names(node) == "bob" ] which is complicated when node is the result of an inline computation and instead we use node["bob", all = TRUE].

Value

A list or single element containing the children of the XML node given by obj and identified by ....

Author(s)

Duncan Temple Lang

References

https://www.w3.org/XML/, https://www.omegahat.net/RSXML/

See Also

xmlAttrs [<-.XMLNode [[<-.XMLNode

Examples

 f = system.file("exampleData", "gnumeric.xml", package = "XML")

 top = xmlRoot(xmlTreeParse(f))

  # Get the first RowInfo element.
 top[["Sheets"]][[1]][["Rows"]][["RowInfo"]]

  # Get a list containing only the first row element
 top[["Sheets"]][[1]][["Rows"]]["RowInfo"]
 top[["Sheets"]][[1]][["Rows"]][1]

  # Get all of the RowInfo elements by position
 top[["Sheets"]][[1]][["Rows"]][1:xmlSize(top[["Sheets"]][[1]][["Rows"]])]

  # But more succinctly and accurately, get all of the RowInfo elements
 top[["Sheets"]][[1]][["Rows"]]["RowInfo", all = TRUE]

XML documentation built on June 25, 2024, 5:06 p.m.