flatten/unflatten data frame
Converts list columns that containing all atomic elements into character vectors and vice versa (for appropriate named variables according to the rtweet package)
Data frame with list columns or converted-to-character (flattened) columns.
If recursive list columns are contained within the data frame, relevant columns will still be converted to atomic types but output will also be accompanied with a warning message.
`flatten` flattens list columns by pasting them into a single string for each observations. For example, a tweet that mentions four other users, for the mentions_user_id variable, it will include the four user IDs separated by a space.
`unflatten`` splits on spaces to convert into list columns any columns with the following names: hashtags, symbols, urls_url, urls_t.co, urls_expanded_url, media_url, media_t.co, media_expanded_url, media_type, ext_media_url, ext_media_t.co, ext_media_expanded_url, mentions_user_id, mentions_screen_name, geo_coords, coords_coords, bbox_coords, mentions_screen_name
If flattened, then data frame where non-recursive list columns---that is, list columns that contain only atomic, or non-list, elements---have been converted to character vectors. If unflattened, this function splits on spaces columns originally returned as lists by functions in rtweet package. See details for more information.