SCARD command in redis

SCARD key

Return the set cardinality (number of elements). If the key does not exist 0 is returned, like for empty sets.

TIME COMPLEXITY: O(1)

RETURN VALUE: The cardinality (number of elements) of the set as an integer.

Syntax:

SCARD key

Example 1: When the key is present

redis:6379> SADD redisKey 100
(integer) 1
redis:6379> SADD redisKey 200
(integer) 1
redis:6379> SCARD redisKey
(integer) 2

Output

2

Example 2: When the key is not present

redis:6379> SCARD redisKey
(integer) 0

Output

0