R: Using dplyr to link 2 objects (Github stats API example) - r

Question

This is the structure of the github stats api data for a repository. I am using dplyr and tidy_json libraries to list the number of commits ("c") ,deletes("d"), lines of code added("a") and the corresponding week("w") for every user in a repository.
{
"total": 5,
"weeks": [
{
"w": 1428192000,
"a": 0,
"d": 0,
"c": 0
},
{
"w": 1428796800,
"a": 0,
"d": 0,
"c": 0
}
],
"author": {
"login": "ttuser1234",
"id": 111111111
}
},
{
"total": 18,
"weeks": [
{
"w": 1428192000,
"a": 212,
"d": 79,
"c": 5
},
{
"w": 1428796800,
"a": 146,
"d": 67,
"c": 1
}
],
"author": {
"login": "coder1234",
"id": 22222222
}
}
}
I am able to extract the weeks and author data separately, but then I am unable to join them together.
inp_file=read_json("The JSON file")
dat=as.tbl_json(inp_file)
dat%>%
enter_object("weeks") %>%
gather_array %>%
spread_values(week=jstring("w"),add=jstring("a"),del=jstring("d"),comm=jstring("c"))
enter_object("author") %>%
spread_values(handle=jstring("login"))
At no point am I able to jump from the author object to the weeks object to link the 2 of them. Is there any way I can do this? Appreciate any help.

Answer 1

tidyjson is nice, but I am not sure it is necessary in this case. Here is one way to achieve what I think is the desired result.
library(jsonlite)
library(dplyr)
df1 <- fromJSON(
'
[
{
"total": 5,
"weeks": [
{
"w": 1428192000,
"a": 0,
"d": 0,
"c": 0
},
{
"w": 1428796800,
"a": 0,
"d": 0,
"c": 0
}
],
"author": {
"login": "ttuser1234",
"id": 111111111
}
},
{
"total": 18,
"weeks": [
{
"w": 1428192000,
"a": 212,
"d": 79,
"c": 5
},
{
"w": 1428796800,
"a": 146,
"d": 67,
"c": 1
}
],
"author": {
"login": "coder1234",
"id": 22222222
}
}
]
'
)
# now the weeks column will actually be nested data.frames
# we can sort of join the weeks with the author information
# like this
df_joined <- df1 %>%
do(
data.frame(
.[["author"]],
bind_rows(.[["weeks"]])
)
)

Answer 2

Solution with tidyjson. It looks like your JSON has a bit of trouble in it, and that it perhaps should be an array? Fixed version below.
Using the development version from devtools::install_github('jeremystan/tidyjson')
In any case, it is not necessary to enter_object for both objects. Rather, you can use a more complex path to grab the handle for author before entering the weeks object.
json <- '[
{
"total": 5,
"weeks": [
{
"w": 1428192000,
"a": 0,
"d": 0,
"c": 0
},
{
"w": 1428796800,
"a": 0,
"d": 0,
"c": 0
}
],
"author": {
"login": "ttuser1234",
"id": 111111111
}
},
{
"total": 18,
"weeks": [
{
"w": 1428192000,
"a": 212,
"d": 79,
"c": 5
},
{
"w": 1428796800,
"a": 146,
"d": 67,
"c": 1
}
],
"author": {
"login": "coder1234",
"id": 22222222
}
}
]'
json %>% as.tbl_json %>%
gather_array() %>%
spread_values(handle=jstring('author','login')) %>% ## useful tip
enter_object("weeks") %>%
gather_array %>%
spread_values(week=jstring("w"),add=jstring("a")
,del=jstring("d"),comm=jstring("c"))
# A tbl_json: 4 x 8 tibble with a "JSON" attribute
# `attr(., "JSON")` document.id array.index handle array.index.2 week add del comm
# <chr> <int> <int> <chr> <int> <chr> <chr> <chr> <chr>
#1 {"w":1428192000... 1 1 ttuser1234 1 1428192000 0 0 0
#2 {"w":1428796800... 1 1 ttuser1234 2 1428796800 0 0 0
#3 {"w":1428192000... 1 2 coder1234 1 1428192000 212 79 5
#4 {"w":1428796800... 1 2 coder1234 2 1428796800 146 67 1
Of course, you can always split the data into two separate pipelines, but this seems like a nicer solution for this example.