CODEWITHSUNDEEP
jsonrmongolite
kannan k
kannan k

Reputation: 145

R -How to pass value in mongolite Query

I'm using mongolite package to connect and retrieve data from MongoDB.How to pass value in mongolite find query

##connecting mongodb

library(mongolite)

mongo<-mongolite::mongo(collection = "Sample", db = "Test", url = 
                          "mongodb://User:123@Wyyuyu:13333/ty2_U",verbose = TRUE)

## getting all data from collection data from collection below query is working fine.

values <- mongo$find()

## But I want to filter specific value by passing value.

 for(i in c("process","check","queue"))
{    

   values <- mongo$find('{"field" : i}',)
}

if I tried above code i'm getting getting below issues . please help me to resolve 

Error: Invalid JSON object: {"field" : i}

Upvotes: 4

Views: 3244

Answers (2)

Karoline Dutra
Karoline Dutra

Reputation: 1

The answers didn't work for me, but helped to start a new construction. So, thank you all.

I'm working with a huge quantity of items, thus I've stored the list in a vector and after I did the loop. In the loop I replaced the "paste0" for a "list" and I used "jsonlite::toJSON" to do the query, remove the [] is essential, so use "auto_unbox = TRUE".

Example:

items <- c("process","check","queue")

final_dataframe <- data.frame() #empty dataframe to store all results
for(i in items) {    

   values <- list(field = i) #vector in a correct format to query in mongolite using jsonlite
   query_items <- mongo$find(jsonlite::toJSON(values, auto_unbox = TRUE), fields = '{}')  #auto_unbox = TRUE to remove brackets and fields = '{}' to get "_id"
   
# filter relevant columns
   query_items <- query_items %>%
     select(`_id`, createdAt, deletedAt) %>%
     mutate(items = i) #storing the items name/id

   final_dataframe <- rbind(final_dataframe, query_items) #to store all results in a dataframe
}

Upvotes: 0

SymbolixAU
SymbolixAU

Reputation: 26248

Given your i is a variable, you need to create the string using something like paste0: 

values <- mongo$find(paste0('{"field" : ', i, '}') )

but rather than a loop you could also use

values <- mongo$find('{"field" : { "$in" : [ "process", "check", "queue" ] } }')

Upvotes: 8

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