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 rank
ZREVRANK to get the rank of an element with the scores ordered from high
memberexists in the sorted set, @integer-reply: the rank of
memberdoes not exist in the sorted set or
keydoes not exist, @bulk-reply:
ZADD myzset 1 "one" ZADD myzset 2 "two" ZADD myzset 3 "three" ZRANK myzset "three" ZRANK myzset "four"