Top-N queries in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the top 3 scores from the sorted set 'game_scores'.

Redis

ZREVRANGE game_scores 0 [1] WITHSCORES

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

A4

B3

C2

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 as stop index returns 4 elements, not 3.

Using -1 returns all elements, not top 3.

The command ZREVRANGE with start 0 and stop 2 returns the top 3 elements (0-based index).

2fill in blank

medium

Complete the code to get the top 5 scores in descending order from 'game_scores'.

Redis

ZREVRANGE game_scores 0 [1] WITHSCORES

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

A4

B5

C3

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 5 as stop index returns 6 elements.

Using ZRANGE instead of ZREVRANGE returns lowest scores first.

ZREVRANGE returns elements in descending order. To get top 5, use stop index 4.

3fill in blank

hard

Fix the error in the code to get the top 3 scores with their members from 'game_scores'.

Redis

ZREVRANGE game_scores 0 [1] WITHSCORES

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

A-1

B2

C-3

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 returns 4 elements.

Using negative indexes may cause unexpected results.

The stop index should be 2 to get exactly 3 elements (0,1,2).

4fill in blank

hard

Fill both blanks to get the top 4 scores with their members in descending order from 'game_scores'.

Redis

ZREVRANGE game_scores [1] [2] WITHSCORES

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

A0

B3

C4

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 4 as stop index returns 5 elements.

Using -1 as stop returns all elements.

Start at 0 and stop at 3 to get top 4 elements (0,1,2,3) in descending order.

5fill in blank

hard

Fill all three blanks to get the top 3 scores with their members from 'game_scores' using ZREVRANGEBYSCORE for scores between 100 and 200.

Redis

ZREVRANGEBYSCORE game_scores [1] [2] LIMIT 0 [3] WITHSCORES

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

A100

B200

C3

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping min and max values.

Using wrong limit count.

The command gets members with scores between 100 and 200, limiting to top 3 results.