Error in Parsing Json to Dataframe R

Question

I am getting below mentioned error while passing Json dataframe.

Error in data.frame(Addr = "London", companyName = "Eagle SUITS",  : 
  arguments imply differing number of rows: 1, 0, 2 In addition: Warning message:
In data.frame(Addr = "NA", companyName = "SAMTEK ENTERPRISES",  :
  row names were found from a short variable and have been discarded

my data frame:

view(df_1)

json_data                id
{Data in json format}    123
{Data in json format}    456
{Data in json format}    789

I am using below mentioned code:

library(jsonlite)
json_dfs <- mapply(f, df_1$json_data, df_1$id, SIMPLIFY = FALSE)

The JSON file content from OP: view(df_1$json_data)

Please provide a small sample of the json file ([make your example reproducible](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example)). — Roman Luštrik, Jan 28 '18 at 12:56
@RomanLuštrik can you provide me your e-mail id so that i can share the R file. — Vector JX, Jan 28 '18 at 12:59
@VectorJX you can simply takeout a small part from `json file` and share with your post. I hope you can do that little to get help from others. — MKR, Jan 28 '18 at 13:38
@RomanLuštrik Uploaded the sample json for one case in answer tab. — Vector JX, Jan 28 '18 at 13:57
@RomanLuštrik uploaded the sample json for one case in answer tab. — Vector JX, Jan 28 '18 at 13:58
I'm busy working on something. Please give me few hours and I will come with some help. — MKR, Jan 28 '18 at 15:44
I'm back to my desk and looking for problem now. Where is definition of `f` function that you have passed to `mapply`? Please share. — MKR, Jan 28 '18 at 19:54
# 1) First, make a transformation function that works for a single entry f <- function(json, id){ # transform json to list tmp <- jsonlite::fromJSON(json) # transform list to data.frame tmp <- as.data.frame(tmp) # add id tmp$id <- id # return return(tmp) } — Vector JX, Jan 28 '18 at 19:58
@VectorJX My 1st suggestion: dont convert to data.frame in function. Change the line `tmp <- as.data.frame(tmp); tmp$id <- id` to `tmp <- c(tmp, ID = id)` — MKR, Jan 28 '18 at 20:13
@VectorJX It must work. I have modified your function and used `json` data provided by your for each IDs (3 in total) to test that it returns `list`. Hope it will help you. — MKR, Jan 28 '18 at 20:53

score 0 · Accepted Answer · answered Jan 28 '18 at 20:52

The issue seems to be in function f which is used to transform json data and merge ID with JSON. The JSON data is nested data, hence it would be better to append as part of list created after parsing json and then convert it to desired format.

I suggest to modify function as:

f_JSON_Transform <- function(json, id){ 
  # transform json to list 
  tmp <- jsonlite::fromJSON(json) 
  # Append ID in list 
  tmp <- c(tmp, ID = id)
  # return 
  return(tmp) 
}
# Below call works without any error
json_lists <- mapply(f_JSON_Transform, df1$json_data, df1$id, SIMPLIFY = FALSE)

#Result
#Output is too long to write here...but it is like
#$test.txt$agreementOfficeAddr
#[1] "NA"

#$test.txt$companyName
#[1] "SAMTEK ENTERPRISES"

#$test.txt$companyAddress
#[1] "E-524,GALI NO- 45, NEAR CHAND MASJID,SHASTRI PARK"
#......
#......

@VectorJX I assume that modified function is able to parse json data, append ID and returns list. That means your 1st problem is solved. Now when you are trying to convert list to dataframe you get errors. Pls analyse result with `str` which can give some clues. — MKR, Jan 29 '18 at 05:40

Error in Parsing Json to Dataframe R

1 Answers1