CODEWITHSUNDEEP
mongodbmongodb-queryaggregation-framework
unltd_J
unltd_J

Reputation: 494

MongoDB aggregate turn list into boolean

I need a query in MongoDB where I turn a list into True or False depending on whether a value exists in the list or not.

Here's a summarized view of the schema.

{'_id': ObjectId('604edf91571e7ab19cc2c238'),
 'timestamp': 1616164767.773929,
 'name': 'some name',
 'metric1': 1,
 'metric2': 2,
 'metric3': 3,
 'tags': ['tag1', 'tag2', 'tag3', 'tag that matters']}

Is there a way to change the tags key to a value of True or False if a 'tag that matters' is in the list? I don't want to exclude records that don't have the tag, I just want those records to have a value of False for the tags key.

Upvotes: 0

Views: 103

Answers (2)

Dheemanth Bhat
Dheemanth Bhat

Reputation: 4452

Try this query:

db.collectionName.aggregate([
    {
        "$addFields": {
            "tags": {
                $map: {
                    input: "$tags",
                    as: "tag",
                    in: {
                        $eq: ['$$tag', 'tag that matters']
                    }
                }
            }
        }
    }
]);

Output:

{
    "_id" : ObjectId("604edf91571e7ab19cc2c238"),
    "timestamp" : 1616164767.773929,
    "name" : "some name",
    "metric1" : 1,
    "metric2" : 2,
    "metric3" : 3,
    "tags" : [
        false,
        false,
        false,
        true
    ]
}

Upvotes: 1

unltd_J
unltd_J

Reputation: 494

need to use an $in operator in the project stage.

{
    "$project": {
        "_id": "$_id",
        "timestamp": "$timestamp",
        "name": "$name",
        "metric1": "$metric1",
        "metric2": "$metric2",
        "metric3": "$metric3",
        "tags": {
            "$in": ["tag that matters", "$tags"]
        }
    }
}

Upvotes: 0

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