how to use mongodb aggregate and retrieve entire documents

Question

I am seriously baffled by mongodb\'s aggregate function. All I want is to find the newest document in my collection. Let\'s say each record has a field \"created\"

Answer 1

query = [
    {
        '$sort': {
            'created': -1
        }
    },
    {
        $group: { 
            '_id':null,
            'max':{'$first':"$$ROOT"}
        }
    }
]
db.collection.aggregate(query)