Generating XML

Abstract

In this chapter, we explore approaches to creating XML content within R. The primary approach is to create nodes and trees that are identical in nature to those returned by the XML parser via the xmlParse() and htmlParse() functions. Rather than generating an entire document in one step, we use functions to build individual nodes, add child nodes and attributes, and set namespaces. We discuss different approaches to building these trees—from top down or bottom up, or a hybrid of both approaches. In some circumstances, where the subtree is large and the nodes have a very regular structure, we can create the XML content more speedily via vectorized string manipulation and then parsing the content into a subtree, thus combining a string-based approach with operating on nodes and trees.