R mongolite: Arrays are loaded from mongo as columns with elements as data.frame

Question

I've been using jsonlite and I used to argument simplifyDataFrame in fromJSON() function. Is there something similar to this in mongolite package? For example using handler argument? I haven't find enough documentation for this method.

I have records similar to

json <- '{"list": [{"x": 1, "y": "a"},{"x": 2, "y": "b"}],"numeric": 1.2}'

When I load the records using find() function it creates data frame with two columns. The first column contains whole data frames as elements.

df <- m$find()
df$list[[1]]
#   x y
# 1 1 a
# 2 2 b

What I want is something like

json %>% fromJSON(simplifyDataFrame = F) %>% as.data.frame.list
#   list.x list.y list.x.1 list.y.1 numeric
# 1      1      a        1        a     1.2

Is there a solution for that?

Edit:

I know that I can do it in a loop to convert the data frame into a list. Or convert the data into JSON format and then use the fromJSON(simplifyDataFrame = F). Both methods are too slow for the size of data I use. See my previous question.

score 4 · Accepted Answer · edited Oct 18 '16 at 01:40

Try using m$iterate()$batch() instead of m$find(). It gives the output you expect.

json <- '{"list": [{"x": 1, "y": "a"},{"x": 2, "y": "b"}],"numeric": 1.2}'
json %>% fromJSON(simplifyDataFrame = F) %>% as.data.frame.list
  list.x list.y list.x.1 list.y.1 numeric
1      1      a        2        b     1.2
catch <- m$insert(json)
m$iterate()$batch() %>% as.data.frame.list
  list.x list.y list.x.1 list.y.1 numeric
1      1      a        2        b     1.2

R mongolite: Arrays are loaded from mongo as columns with elements as data.frame

1 Answers1