ZRANGE and ZREVRANGE for reading in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Redis command ZRANGE do?

It returns a range of members in a sorted set, ordered from the lowest to the highest score.

beginner

How does ZREVRANGE differ from ZRANGE?

ZREVRANGE returns members in a sorted set ordered from the highest to the lowest score, reversing the order of ZRANGE.

beginner

What do the start and stop parameters in ZRANGE key start stop represent?

They specify the index range of elements to return, where 0 is the first element, 1 the second, and so on. Negative numbers count from the end (-1 is last).

intermediate

How can you include the scores of members when using ZRANGE or ZREVRANGE?

Add the WITHSCORES option to the command to get each member's score along with the member.

beginner

If you want to get the top 3 highest scored members from a sorted set, which command would you use?

Use ZREVRANGE key 0 2 to get the first 3 members with the highest scores.

What order does ZRANGE return members from a sorted set?

A Alphabetical order

B From highest to lowest score

C Random order

D From lowest to highest score

ZRANGE returns members ordered by increasing score, from lowest to highest.

Which command returns members from highest to lowest score?

A ZRANGE

B ZREVRANGE

C ZADD

D ZREM

ZREVRANGE returns members ordered from highest to lowest score.

What does the WITHSCORES option do when used with ZRANGE or ZREVRANGE?

A Returns members and their scores

B Sorts members alphabetically

C Returns only scores

D Deletes members with scores

WITHSCORES returns each member along with its score.

If you want the last 2 members in a sorted set using ZRANGE, what start and stop values do you use?

A 1 2

B 0 1

C -2 -1

D -1 0

Negative indexes count from the end, so -2 -1 gets the last two members.

Which command would you use to get the top 5 lowest scored members?

A ZRANGE key 0 4

B ZREVRANGE key 0 4

C ZRANGE key -5 -1

D ZREVRANGE key -5 -1

ZRANGE key 0 4 returns the first 5 members with the lowest scores.

Explain how ZRANGE and ZREVRANGE commands work in Redis sorted sets.

Think about the order and how you specify which members to get.

Describe how to retrieve the top 3 highest scored members from a Redis sorted set including their scores.

Remember ZREVRANGE reverses the order to highest first.