Redis ZRANK command returns the rank of member in the sorted set stored at the 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 rank 0.
If the member exists in the sorted set, Integer reply: the rank of member.
If the member does not exist in the sorted set or the key does not exist, Bulk string reply − nil.
Following is the basic syntax of Redis ZRANK command.
redis 127.0.0.1:6379> ZRANK key member
redis 127.0.0.1:6379> ZADD myzset 0 a 1 b 2 c 3 d 4 e (integer) 5 redis 127.0.0.1:6379> ZADD myzset 5 f 6 g (integer) 2 redis 127.0.0.1:6379> ZRANK myzset b (integer) 1 redis 127.0.0.1:6379> ZRANK myzset t nil