ZRANK command in redis

ZRANK key member

Returns the rank of member in the sorted set stored at key, with the scores ordered from low to high. The rank (or index) is 0-based, which means that the member with the lowest score has a rank of 0.

TIME COMPLEXITY: O(log(N))

RETURN VALUE:

If a member exists in the sorted set, Integer reply: the rank of the member.

If the member does not exist in the sorted set or key does not exist, Bulk reply: nil.

Syntax:

ZRANK key member

Example 1: When the member is present

redis:6379> ZADD mykey 1 A 2 B 3 C 4 D 5 E
(integer) 5
redis:6379> ZRANK mykey A
(integer) 0
redis:6379> ZRANK mykey B
(integer) 1

Example 2: When the member or key is not present

redis:6379> ZADD mykey 1 A 2 B 3 C 4 D 5 E
(integer) 5
redis:6379> ZRANK mykey AA
(nil)

Output

nil