Add JSON column to R dataframe

Question

I have a data frame and want to add an additional column that contains the data per row in JSON format. In this example:

dfr = data.frame(name = c("Andrew", "Mathew", "Dany", "Philip", "John", "Bing", "Monica"), age = c(28, 23, 49, 29, 38, 23, 29))

dfr %>% mutate(Payload = jsonlite::toJSON(dfr))

I would like to get

Andrew  28   {"name":"Andrew","age":28}
Mathew  23   {"name":"Mathew","age":23}

Instead I get per row the JSON string for the complete data frame. I tried it with apply but I fail to get it to run.

Related: https://stackoverflow.com/q/25550711/680068 – zx8754 Apr 20 '20 at 10:51 — zx8754, Apr 20 '20 at 10:51

score 4 · Accepted Answer · answered Apr 20 '20 at 10:38

Try running per each row: split every row, then apply toJSON function:

dfr$Payload <- sapply(split(dfr, seq(nrow(dfr))), toJSON)

dfr
#     name age                      Payload
# 1 Andrew  28 [{"name":"Andrew","age":28}]
# 2 Mathew  23 [{"name":"Mathew","age":23}]
# 3   Dany  49   [{"name":"Dany","age":49}]
# 4 Philip  29 [{"name":"Philip","age":29}]
# 5   John  38   [{"name":"John","age":38}]
# 6   Bing  23   [{"name":"Bing","age":23}]
# 7 Monica  29 [{"name":"Monica","age":29}]

@StefanG read about purrr to use pipes. Can't find a relevant post at the moment. — zx8754, Apr 20 '20 at 11:15

Add JSON column to R dataframe

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