$pull operator for removing from arrays in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove all elements equal to 5 from the 'scores' array.

MongoDB

db.students.updateOne({name: 'Alice'}, {$pull: {scores: [1])

Drag options to blanks, or click blank then click option'

A"5"

B5

C{ $eq: 5 }

D[5]

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around numbers removes strings, not numbers.

Passing an array instead of a value causes errors.

The $pull operator removes all instances of the specified value from the array. Here, 5 is the value to remove.

2fill in blank

medium

Complete the code to remove all elements greater than 10 from the 'grades' array.

MongoDB

db.courses.updateMany({}, {$pull: {grades: { [1]: 10 }}})

Drag options to blanks, or click blank then click option'

A$eq

B$lt

C$gt

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt removes elements less than 10, which is wrong here.

Using $eq removes only elements equal to 10.

The $gt operator means 'greater than'. It removes all elements greater than 10.

3fill in blank

hard

Fix the error in the code to remove all elements less than or equal to 3 from the 'values' array.

MongoDB

db.data.updateOne({}, {$pull: {values: { [1]: 3 }}})

Drag options to blanks, or click blank then click option'

A$gte

B$eq

C$lt

D$lte

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt excludes elements equal to 3.

Using $gte removes elements greater than or equal to 3, which is opposite.

The $lte operator means 'less than or equal to', which matches the requirement.

4fill in blank

hard

Fill both blanks to remove all elements that are strings equal to 'remove' from the 'tags' array.

MongoDB

db.collection.updateMany({}, {$pull: {tags: { [1]: [2] }}})

Drag options to blanks, or click blank then click option'

A$eq

B"remove"

C'remove'

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using $ne removes elements not equal to the value, which is wrong.

Using single quotes may cause syntax issues in some environments.

The $eq operator matches elements equal to the given value. The value must be a string, so quotes are needed.

5fill in blank

hard

Fill both blanks to remove all elements from the 'items' array where the 'price' field is less than 20.

MongoDB

db.store.updateOne({id: 1}, {$pull: {items: { [1]: { [2]: 20 }}}})

Drag options to blanks, or click blank then click option'

Aprice

B$lt

Dcost

Attempts:

3 left

💡 Hint

Common Mistakes

Using cost instead of price as field name.

Using $gt instead of $lt operator.

The field to check is price. The operator for 'less than' is $lt. The query removes items with price less than 20.