I have a data frame in R that i want to serialize into json in a particular format. Sample code:
df_t<-data.frame(c(453:458),c(1:6), row.names = NULL)
colnames(df_t) <- c("area", "price")
jsonlite::toJSON(df_t)
The format of output of above code is as below:
[{"area":453,"price":1},{"area":454,"price":2},{"area":455,"price":3},{"area":456,"price":4},{"area":457,"price":5},{"area":458,"price":6}]
But the format I want is:
{"area":[453,454,455,456,457,458],"price":[1,2,3,4,5,6]}
To get the format I require i have written this bit of code which gives me similar output to what i expect but enclosed in quotes:
paste0( '{', colnames(df_t)[1], ':', jsonlite::toJSON(df_t[,1]), ',', colnames(df_t)[2], ':', jsonlite::toJSON(df_t[,2]), '}')
"{area:[453,454,455,456,457,458],price:[1,2,3,4,5,6]}"
My question is that is there a better way to get the format I want? The dataframe is being returned from a R plumber api and so is using jsonlite serializer by default.
json and the jsonlite package lend themselves more readily to the list format.
It could be that altering the default serialization is more work than simply converting the R data structure to match.
I would suggest something along the lines of
df_t<-data.frame(c(453:458),c(1:6), row.names = NULL)
colnames(df_t) <- c("area", "price")
df_t_list <- list()
for(i in 1:ncol(df_t)) {
df_t_list[[i]] <- df_t[ , i]
}
names(df_t_list) <- c("area", "price")
jsonlite::toJSON(df_t_list)