ZRANGEBYLEX for lexicographic queries in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Redis command ZRANGEBYLEX do?

ZRANGEBYLEX returns members in a sorted set within a specified lexicographic range.

It sorts by dictionary order, not by score.

beginner

How do you specify an inclusive range in ZRANGEBYLEX?

Use square brackets [ before the value.

Example: [apple means include 'apple' in the range.

beginner

What symbols indicate exclusive range boundaries in ZRANGEBYLEX?

Use parentheses ( before the value.

Example: (apple means exclude 'apple' from the range.

beginner

What do the special values - and + mean in ZRANGEBYLEX?

- means the smallest possible value (start of range).

+ means the largest possible value (end of range).

beginner

Can ZRANGEBYLEX be used to query by score in Redis sorted sets?

No. ZRANGEBYLEX queries by lexicographic order of members, ignoring scores.

Use ZRANGEBYSCORE to query by score.

What does ZRANGEBYLEX myset [a (c return?

A Members from 'a' exclusive up to 'c' inclusive

B Members from 'a' inclusive up to 'c' exclusive

C Members from 'a' exclusive up to 'c' exclusive

D Members from 'a' inclusive up to 'c' inclusive

Square bracket [ means inclusive, parenthesis ( means exclusive.

So range is from 'a' inclusive to 'c' exclusive.

Which command would you use to get all members lexicographically greater than 'mango'?

A ZRANGEBYLEX myset (mango +

B ZRANGEBYLEX myset [mango +

C ZRANGEBYSCORE myset (mango +

D ZRANGEBYLEX myset - (mango

(mango means exclude 'mango', + means max value.

This returns members greater than 'mango'.

What does the - symbol mean in ZRANGEBYLEX?

A Include the member

B Largest possible member

C Exclude the member

D Smallest possible member

- means the smallest possible member in lexicographic order.

If you want to include 'banana' in the range, which prefix do you use?

A [banana

B (banana

C -banana

D +banana

Square bracket [ means include the member.

Can ZRANGEBYLEX return members sorted by their scores?

A Yes, if you specify a score range

B Yes, it sorts by score

C No, it sorts by lexicographic order only

D No, it returns random members

ZRANGEBYLEX sorts members by their lexicographic order, ignoring scores.

Explain how to use ZRANGEBYLEX to get members between two lexicographic values, including how to specify inclusive and exclusive ranges.

Think about how dictionary order works and how to include or exclude boundary words.

Describe the difference between ZRANGEBYLEX and ZRANGEBYSCORE in Redis sorted sets.

One sorts by words, the other by numbers.