如何在Mongo DB查询中传递列表

Question

This works when I am dynamically querying by just one particular value of col but incase my col is an array eg: c("red","blue"), it is failing.

Working for single value

col<-"red"
pipe1 <- paste("{\"$match\":{\"color\":\"",col,"\"}}", sep = "")    
query1 <-   list(    
mongo.bson.from.JSON(pipe1),   
mongo.bson.from.JSON('     
                       {
                       "$project" : {   
                       "_id" : 0,   
                       "Email":"$email",  
                       "color":"$color" }    
                       }')) 

Any solutions? Using this to convert Json to dataframe in R

Answer 1

If col is an array, like you say, then the string it produces wouldn't be valid JSON. I think it would be something like:

{"$match":{"color": "red", "blue" }}

When what you need is:

{"$match":{"color": ["red", "blue"] }}