One of things that makes R great is the wealth of high-quality add-on packages. As you might expect, there are many of these add-on packages with the ability to import data in a multitude of other formats. Whether it's an arcane markup language, a proprietary binary file, Excel spreadsheet, and so on, there is almost certainly an R package out there for you to handle it. But how do you find them?
One way is to browse the community maintained CRAN Task Views (https://cran.r-project.org/web/views/). A Task View is a way to browse for packages related to a particular topic, domain, or special interest. The germane Task View, here, is the Web Technologies Task View (https://cran.r-project.org/web/views/WebTechnologies.html). You'll notice that jsonlite
and the XML
package are mentioned on the first page.
The easiest way to discover these packages, though, is through your favorite web browser. For example, if you are looking for a package to import YAML data (yet another data...