Mongo nested documents read in R

Question

I have a mongodb database and I calculated prediction using my mongo documents in R, for this I used the R rmongodb library. I can read documents which have a simple key value. However, I don't know how to read nested mongo data in R. Does any one know how to access nested documents in R?

Did you see [this question & answer](http://stackoverflow.com/questions/12003402/queries-in-mongodb/12074341#12074341)? — Jaap, May 08 '14 at 07:51

score 0 · Answer 1 · answered Jun 16 '14 at 17:42

It really depends on what you wanna read from the BSON structure.

For maps like this {'mapping': {'a':123, 'b':456}}, it's as easy as

mongo.bson.value(cval,"mapping.a")

or

mongo.bson.value(cval,"mapping.b")

However, for list structure like this {'list':[1,2,3,4,5]}, you need to use a loops to read them out:

for (item in mongo.bson.value(cval,"list")) {
    print(item)
 }

You can find the whole example in this tutorial: http://winston.attlin.com/2014/01/building-up-easy-data-analysis-platform.html

Mongo nested documents read in R

1 Answers1