Why sorted sets solve ranking problems in Redis - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a member with a score to a sorted set in Redis.

Redis

ZADD leaderboard 1500 [1]

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

AZADD

B1500

Cscore

Dplayer1

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the member name before the score.

Using a string instead of a number for the score.

The ZADD command requires the score before the member name. Here, 1500 is the score.

2fill in blank

medium

Complete the code to retrieve the top 3 members with the highest scores from the sorted set.

Redis

ZREVRANGE leaderboard 0 [1] WITHSCORES

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

A3

B1

C2

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 as the end index, which returns 4 members.

Using ZRANGE instead of ZREVRANGE for highest scores.

Indexes start at 0, so to get the top 3 members, use 0 2 as the range.

3fill in blank

hard

Fix the error in the code to get the rank of 'player5' in ascending order.

Redis

ZRANK leaderboard [1]

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

Aplayer5

B5

Crank

Dplayer

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of the member name.

Confusing ZRANK with ZREVRANK.

The ZRANK command requires the member name to find its rank.

4fill in blank

hard

Fill both blanks to increment the score of 'player3' by 100 in the sorted set.

Redis

ZINCRBY leaderboard [1] [2]

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

A100

Bplayer3

C150

Dplayer1

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the increment and member arguments.

Using a member name that does not exist.

ZINCRBY takes the key, the increment amount, and the member name in that order.

5fill in blank

hard

Fill both blanks to remove members with scores between 1000 and 2000 from the sorted set.

Redis

ZREMRANGEBYSCORE leaderboard [1] [2]

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

A1000

B2000

C-inf

D+inf

Attempts:

3 left

💡 Hint

Common Mistakes

Using -inf or +inf incorrectly.

Swapping the min and max values.

ZREMRANGEBYSCORE removes members with scores in the given range, inclusive.