Conditional expressions ($cond, $switch) in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to use $cond to check if the field 'score' is greater than 50.

MongoDB

{ $cond: { if: { $gt: ["$score", [1]] }, then: "Pass", else: "Fail" } }

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

A50

B100

C0

D75

Attempts:

3 left

💡 Hint

Common Mistakes

Using a value other than 50 for the comparison.

Confusing $gt with $lt.

The $cond expression checks if 'score' is greater than 50. If true, it returns "Pass", else "Fail".

2fill in blank

medium

Complete the $cond expression to return 'High' if 'age' is at least 18, otherwise 'Low'.

MongoDB

{ $cond: { if: { $gte: ["$age", [1]] }, then: "High", else: "Low" } }

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

A18

B16

C20

D21

Attempts:

3 left

💡 Hint

Common Mistakes

Using 21 instead of 18.

Using $gt instead of $gte.

$gte means 'greater than or equal to'. We check if age is at least 18 to return 'High'.

3fill in blank

hard

Fix the error in the $switch expression to correctly return 'Child', 'Teen', or 'Adult' based on 'age'.

MongoDB

{ $switch: { branches: [ { case: { $lt: ["$age", [1]] }, then: "Child" }, { case: { $lt: ["$age", 20] }, then: "Teen" } ], default: "Adult" } }

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

A21

B13

C18

D16

Attempts:

3 left

💡 Hint

Common Mistakes

Using 13 or 16 instead of 18 for the first case.

Not ordering cases properly.

The first case should check if age is less than 18 to classify as 'Child'. Then less than 20 is 'Teen'. Otherwise, 'Adult'.

4fill in blank

hard

Fill both blanks to create a $cond expression that returns 'Adult' if age is 18 or more, else 'Minor'.

MongoDB

{ $cond: { if: { $[1]: ["$age", [2]] }, then: "Adult", else: "Minor" } }

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

Agte

Blt

C18

D21

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt instead of $gte.

Using 21 instead of 18.

Use $gte to check if age is greater than or equal to 18 to return 'Adult'. Otherwise, return 'Minor'.

5fill in blank

hard

Fill all three blanks to create a $switch expression that returns 'Low', 'Medium', or 'High' based on 'score'.

MongoDB

{ $switch: { branches: [ { case: { $lt: ["$score", [1]] }, then: "Low" }, { case: { $lt: ["$score", [2]] }, then: "Medium" } ], default: [3] } }

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

A50

B80

C"High"

D"Medium"

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of thresholds.

Using incorrect default value.

The first case checks if score is less than 50 for 'Low'. The second checks less than 80 for 'Medium'. Otherwise, 'High'.