SUNION, SINTER, SDIFF set operations in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Redis command SUNION do?

It returns all the unique members from all the given sets combined, like gathering all friends from different groups without repeats.

beginner

Explain the Redis command SINTER in simple terms.

It finds the common members that exist in all the given sets, like finding friends who are in every group you belong to.

beginner

What is the purpose of the Redis command SDIFF?

It returns members from the first set that are not in the other sets, like finding friends unique to your first group and not in others.

beginner

If you run SUNION set1 set2 and set1 has {a, b} and set2 has {b, c}, what is the result?

The result is {a, b, c} because SUNION combines all unique members from both sets.

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What will SINTER set1 set2 return if set1 = {x, y, z} and set2 = {y, z, w}?

It will return {y, z} because those members are common to both sets.

Which Redis command returns all unique members from multiple sets combined?

A SDIFF

B SINTER

C SUNION

D SMEMBERS

SUNION returns the union of all members from the given sets.

What does SINTER return when used on sets?

A Members common to all sets

B All members from all sets combined

C The size of the sets

D Members unique to the first set

SINTER returns members that exist in every set provided.

If set1 = {1, 2, 3} and set2 = {2, 4}, what does SDIFF set1 set2 return?

A {1, 3}

B {1, 2, 3, 4}

C {2}

D {}

SDIFF returns members in set1 not in set2, so {1, 3}.

Which command would you use to find members that are in both setA and setB?

A SUNION setA setB

B SINTER setA setB

C SDIFF setA setB

D SADD setA setB

SINTER finds the intersection (common members) of sets.

What will SUNION return if one of the sets is empty?

A Members only from the empty set

B An empty set

C Error

D Only members from the non-empty sets

SUNION returns all unique members from all sets, ignoring empty ones.

Describe in your own words what the Redis commands SUNION, SINTER, and SDIFF do with sets.

Think about combining friends from groups, common friends, and unique friends.

Give a real-life example to explain when you would use SUNION, SINTER, and SDIFF in Redis.

Imagine groups of friends or shopping lists.