Manipulating parsed JSON

As you saw in the video, the output from parsing JSON is a list. One way to extract relevant data from that list is to use a package specifically designed for manipulating lists, rlist.

rlist provides two particularly useful functions for selecting and combining elements from a list: list.select() and list.stack(). list.select() extracts sub-elements by name from each element in a list. For example using the parsed movies data from the video (movies_list), we might ask for the title and year elements from each element:

list.select(movies_list, title, year)

The result is still a list, that is where list.stack() comes in. It will stack the elements of a list into a data frame.

list.stack(
    list.select(movies_list, title, year)
)

In this exercise you'll use these rlist functions to create a data frame with the user and timestamp for each revision.

First, you'll need to figure out where the revisions are. Examine the output from the str() call. Can you see where the list of 5 revisions is?
Store the revisions in revs.
Use list.select() to pull out the user and timestamp elements from each revision, store in user_time.
Print user_time to verify it's a list with one element for each revision.
Use list.stack() to stack the lists into a data frame.

Take Hint (-30 XP)

Exercise

Manipulating parsed JSON

Instructions