How to delete element from an array in MongoDB?

To delete element from an array in MongoDB, use the $pull operator. This operator removes all instances of a specified value from an array field.

Syntax

db.collection.update(
    { query },
    { $pull: { arrayField: valueToRemove } },
    { multi: true }
);

Create Sample Data

Let us create a collection with documents −

db.demo279.insertMany([
    { id: [101, 103, 105, 110] },
    { id: [107, 111, 110] }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e490af7dd099650a5401a58"),
        ObjectId("5e490b06dd099650a5401a59")
    ]
}

Display all documents from the collection −

db.demo279.find();

{ "_id": ObjectId("5e490af7dd099650a5401a58"), "id": [101, 103, 105, 110] }
{ "_id": ObjectId("5e490b06dd099650a5401a59"), "id": [107, 111, 110] }

Example: Remove Element from Array

Following is the query to delete element 110 from all arrays −

db.demo279.update(
    {},
    { $pull: { id: 110 } },
    { multi: true }
);

WriteResult({ "nMatched": 2, "nUpserted": 0, "nModified": 2 })

Verify Result

Display all documents to verify the deletion −

db.demo279.find();

{ "_id": ObjectId("5e490af7dd099650a5401a58"), "id": [101, 103, 105] }
{ "_id": ObjectId("5e490b06dd099650a5401a59"), "id": [107, 111] }

Key Points

• $pull removes all instances of the specified value from the array
• Use multi: true to update multiple documents
• The operator works on all array elements that match the specified value

Conclusion

The $pull operator efficiently removes specific values from arrays across multiple documents. Use multi: true to apply the deletion to all matching documents in the collection.