How to query MongoDB from R?

Question

I want to get a MongoDB query from R.

With the mongo shell, I would query with:

db.user.find({age:{$gt:21}})

However, In R-Mongo, I haven't found how to describe this query.

Thanks

Answer 1

If you are using rmongodb (there is a similar package called Rmongo):

     r <- mongo.find(mongo, "test.user", list(age=list('$gt'=21L)))

the BSON query object can also be built like so:

     buf <- mongo.bson.buffer.create()
     mongo.bson.buffer.start.object(buf, "age")
     mongo.bson.buffer.append(buf, "$gt", 21L)
     mongo.bson.buffer.finish.object(buf)
     query <- mongo.bson.from.buffer(buf)
     r <- mongo.find("mongo", "test.user", query)