$slice modifier with $push in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a value to the 'scores' array using $push.

MongoDB

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

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

A95

B[95]

C{95}

D"95"

Attempts:

3 left

💡 Hint

Common Mistakes

Using brackets [] which adds an array instead of a single value.

The $push operator adds a single value to an array. Here, 95 is the value to add.

2fill in blank

medium

Complete the code to limit the 'scores' array to the last 3 elements after pushing a new score.

MongoDB

db.students.updateOne({name: 'Bob'}, {$push: {scores: {$each: [88], [1]: -3}}})

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

A$count

B$limit

C$max

D$slice

Attempts:

3 left

💡 Hint

Common Mistakes

Using $limit which is not valid in this context.

The $slice modifier limits the array size after pushing. Using -3 keeps the last 3 elements.

3fill in blank

hard

Fix the error in the code to correctly push multiple scores and keep only the last 5.

MongoDB

db.students.updateOne({name: 'Carol'}, {$push: {scores: {$each: [1], $slice: -5}}})

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

A"70, 75, 80"

B{70, 75, 80}

C[70, 75, 80]

D70, 75, 80

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces {} which is for objects, not arrays.

$each expects an array of values. Use square brackets [] to provide multiple scores.

4fill in blank

hard

Fill both blanks to push scores and keep only the first 4 elements in the array.

MongoDB

db.students.updateOne({name: 'Dave'}, {$push: {scores: {$each: [1], [2]: 4}}})

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

A[85, 90]

B$slice

C$limit

D$count

Attempts:

3 left

💡 Hint

Common Mistakes

Using $limit which is not a valid modifier here.

Use $each with an array to push multiple values, and $slice with a positive number to keep the first elements.

5fill in blank

hard

Fill all three blanks to push a score, keep last 3 elements, and sort scores descending.

MongoDB

db.students.updateOne({name: 'Eve'}, {$push: {scores: {$each: [[1]], [2]: -3, [3]: -1}}})

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

A92

B$slice

C$sort

D$limit

Attempts:

3 left

💡 Hint

Common Mistakes

Using $limit which is not a valid modifier here.

Push score 92, use $slice to keep last 3 elements, and $sort with -1 to sort descending.