How do I delete array value from a document in MongoDB?

To delete array values from a document in MongoDB, use the $pull operator. The $pull operator removes from an existing array all instances of a value or values that match a specified condition.

Syntax

db.collection.update(
    { "matchCondition": "value" },
    { $pull: { "arrayField": "valueToRemove" } }
);

Create Sample Data

Let us first create a collection with documents ?

db.demo535.insertOne({
    "studentId": "101",
    "studentName": "Chris",
    "ListOfMailIds": [
        "Chris@gmail.com",
        "Chris@yahoo.com"
    ]
});

{
    "acknowledged": true,
    "insertedId": ObjectId("5e8c82bfef4dcbee04fbbc00")
}

Display all documents from a collection with the help of find() method ?

db.demo535.find();

{
    "_id": ObjectId("5e8c82bfef4dcbee04fbbc00"),
    "studentId": "101",
    "studentName": "Chris",
    "ListOfMailIds": ["Chris@gmail.com", "Chris@yahoo.com"]
}

Example: Delete Specific Array Value

Following is the query to delete array value from a document in MongoDB ?

db.demo535.update(
    { _id: ObjectId("5e8c82bfef4dcbee04fbbc00") },
    { $pull: { "ListOfMailIds": "Chris@yahoo.com" } }
);

WriteResult({ "nMatched": 1, "nUpserted": 0, "nModified": 1 })

Verify Result

Display all documents to verify the deletion ?

db.demo535.find();

{
    "_id": ObjectId("5e8c82bfef4dcbee04fbbc00"),
    "studentId": "101",
    "studentName": "Chris",
    "ListOfMailIds": ["Chris@gmail.com"]
}

Conclusion

The $pull operator efficiently removes specific values from arrays in MongoDB documents. It removes all instances of the matching value and automatically maintains the array structure.