Adding a JSON column from specific R dataframe columns

Question

I have an R dataframe with specific columns I want to append together into a JSON column

df = data.frame(item = c("Box 1", "Box 2", "Box 3"), Length = c(2, 4, 6), Width = c(4,5,3), Height  = c(6, 4, 3))

I want a JSON item dimension column in the df data frame with each of the dimensions separated by an "x" in a single item dimensions column.

   item Length Width Height       item dimensions
1 Box 1      2     4      6   {"size":"2 x 4 x 6"}
2 Box 2      4     5      4   {"size":"4 x 5 x 4"}
3 Box 3      6     3      3   {"size":"6 x 3 x 3"}

I tried working with the jsonlite package but not getting the result I want. I am also working within the dplyr package too so a dpylr::mutate solution would be greatly appreciated.

Answer 1

Chris - welcome to SO! This is something to try that uses dplyr. You will want to use rowwise first. The auto_unbox option will remove extra brackets to match your desired output.

library(tidyverse)
library(jsonlite)

df %>%
  rowwise %>%
  mutate(item_dimensions = toJSON(list(size = paste(Length, Width, Height, sep = " x ")), auto_unbox = T))

Output

  item  Length Width Height item_dimensions     
  <chr>  <dbl> <dbl>  <dbl> <json>              
1 Box 1      2     4      6 {"size":"2 x 4 x 6"}
2 Box 2      4     5      4 {"size":"4 x 5 x 4"}
3 Box 3      6     3      3 {"size":"6 x 3 x 3"}