How to Use SMEMBERS Command in Redis: Syntax and Examples

Use the SMEMBERS command in Redis to retrieve all members of a set stored at a given key. It returns all elements as an unordered collection. The syntax is SMEMBERS key, where key is the name of the set.

Syntax

The SMEMBERS command retrieves all members of the set stored at the specified key. If the key does not exist, it returns an empty set.

• key: The name of the set you want to get members from.

redis

SMEMBERS key

Example

This example shows how to add members to a set and then retrieve all members using SMEMBERS.

redis

SADD fruits apple banana orange
SMEMBERS fruits

Output

1) "apple"
2) "banana"
3) "orange"

Common Pitfalls

Common mistakes when using SMEMBERS include:

• Using SMEMBERS on a key that is not a set, which causes an error.
• Expecting the members to be returned in any specific order; sets are unordered.
• Not checking if the key exists, which returns an empty set but might be mistaken for an error.

redis

/* Wrong: Using SMEMBERS on a string key */
SET mykey "hello"
SMEMBERS mykey

/* Right: Use SMEMBERS only on set keys */
SADD myset "hello"
SMEMBERS myset

Output

(error) WRONGTYPE Operation against a key holding the wrong kind of value
1) "hello"

Quick Reference

Command	Description
SMEMBERS key	Returns all members of the set stored at key
SADD key member [member ...]	Adds one or more members to a set
SISMEMBER key member	Checks if a member exists in the set
SCARD key	Returns the number of members in the set

Key Takeaways

SMEMBERS returns all members of a set stored at the given key in Redis.

The returned members are unordered; sets do not guarantee order.

Using SMEMBERS on a non-set key causes an error.

If the key does not exist, SMEMBERS returns an empty set.

Use SADD to add members before retrieving them with SMEMBERS.