16  16. Using JSON in R with jsonlite package

16.1 jsonlite vignettes

The jsonlite R pacakge is used to read JSON files into R. The following is the link to the CRAN webpage for the jsonlite package. See the vignettes and reference manual linked there.

jsonlite: A Simple and Robust JSON Parser and Generator for R

Below, I copied the links to some of the vignettes from that page. However, it’s best to check the official CRAN page in case there are modifications or if there are new vignettes added there (this page was compiled in Jan 2025).

• IMPORTANT: The following describes how to use the fromJSON and toJSON functions from the jsonlite package. Getting started with JSON and jsonlite

• The following will be covered later when we discuss APIs:
  Fetching JSON data from REST APIs (2022-01-16)

• The following is nice to know but is something that you can figure out yourself without needing this:
  Combining pages of JSON data with jsonlite (2022-01-16)

• The following is a more detailed definition of how JSON is converted to R data and how R data is converted to JSON. You should NOT need to look at this but it is nice to know that it is available for reference in case you get stuck.

  A mapping between JSON data and R objects (March 2014)

• There are some other vignettes on the CRAN page, but you probably don’t need to look at them.

16.2 toJSON - create JSON from an R object

16.2.1 pretty argument and prettify function

16.2.2 use writeLines to write the JSON to a file

16.2.3 toJSON(SOME_R_OBJECT , auto_unbox=TRUE)

readLines and writeLines

16.3 fromJSON - create an R object from JSON

16.4 Working with nested dataframes

16.4.1 tidyr - unnest , expand , crossing , nesting (TODO get exmaples from LLMs)