SCARD – Redis

始于1.0.0可用。

时间复杂度： O(1)

Returns the set cardinality (number of elements) of the set stored at key.

返回值

Integer reply: the cardinality (number of elements) of the set, or 0 if key does not exist.

redis> SADD myset "Hello"

(integer) 1

redis> SADD myset "World"

(integer) 1

redis> SCARD myset

(integer) 2