removing duplicate array values from mongodb

Question

In mongodb I have collection where arrays has duplicate entries like

{
    \"_id\": ObjectId(\"57cf3cdd5f20a3b0ba009777\"),
    \"Chat\": 6,
    \"string\":          


        

Answer 1

db.getCollection('Test').aggregate([{
    $unwind: '$string'},
    {
        $group: {
            _id: '$_id', 
            string: {
                $addToSet: '$string'
            }, 
            Chat: {
                $first: '$Chat'
            }
        }
    }
    ]);

O/P: here you are getting 2 "1348157031 Riyadh" because there is an extra space which defines itself as an different entity.

{
    "_id" : ObjectId("57cf3cdd5f20a3b0ba009777"),
    "string" : [ 
        " 1348157031 Riyadh", 
        " 548275320 Mohammad Sumon", 
        "1348157031 Riyadh"
    ],
    "Chat" : 6
}