錯誤：無效的JSON對象

Question

我試圖運行此查詢，並繼續出現此錯誤：

install.packages(“mongolite”)
library(mongolite)

m <- mongo(db = "ionmom")
m6 <- m$aggregate('[{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]')

# Error: Invalid JSON object: [{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]

Answer 1

mongolite在mongolite使用jsonlite進行JSON解析。 如果通過jsonlite::fromJSON()查詢，則會看到問題

js <- '[{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]'

jsonlite::fromJSON(js)

# Error: lexical error: invalid char in json text.
#                  [{"$unwind":"$cdr"}, {$lookup:{from: "inventory", loc
#                      (right here) ------^

這是在告訴您JSON結構無效，因為它期望每個字符串都用引號" "

js <- '[{"$unwind":"$cdr"}, {"$lookup":{"from": "inventory", "localField": "_id", "foreignField": "_id", "as":"inventory"}},{"$unwind": "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]'

m$aggregate(js)

## I don't have your data ...

# Imported 0 records. Simplifying into dataframe...
# data frame with 0 columns and 0 rows

Answer 2

嘗試添加：

js <- '[{"$unwind":"$cdr"}, {"$lookup":{"from": "inventory", localField:}]'