使用rmongodb从mongoDB提取数据

Question

I have the following code in R:

library("rmongodb")

mongo <- mongo.create(<host>)
mongo.is.connected(mongo)
collection<-mongo.get.database.collections(mongo, 'words')
store <-mongo.find.all(mongo,collection)

When I print the store I get:

[[1]] [[1]]$`_id` [1] "56c462be97819a3e6320e595"

[[1]]$word [1] "short"


[[2]] [[2]]$`_id` [1] "56c462c597819a3e6320e596"

[[2]]$word [1] "long"

The problem here is that I don't how to get the the whole word field and how to get a single entry, like 'short' and 'long'.

I've searched for some time and still don't get it.

Answer 1

mongo.get.values(mongo, "words", "word")

Another example:

cursor <- mongo.find(mongo, "words", query='{"word":"short"}')

list <- mongo.cursor.to.list(cursor)

helpful cheatsheet:
https://cran.r-project.org/web/packages/rmongodb/vignettes/rmongodb_cheat_sheet.pdf

hope that helps!