Method ZRevRank

structure/zset.go:705–722

ZRevRank calculates the reverse rank of a member in a ZSet (Sorted Set) associated with a given key. ZSet exploits the Sorted Set data structure of Redis with O(log(N)) time complexity for Fetching the rank. Parameters: key: This is a string that serves as the key of a ZSet stored in the datab

(key string, member string)

//
// Note: The reverse rank is calculated as 'size - rank', and the ranks start from 1.
func (zs *ZSetStructure) ZRevRank(key string, member string) (int, error) {
	if err := checkKey(key); err != nil {
		return 0, err
	}
	keyBytes := stringToBytesWithKey(key)

	zSet, err := zs.getZSetFromDB(keyBytes)
	if err != nil {
		return 0, fmt.Errorf("failed to get or create ZSet from DB with key '%v': %w", key, err)
	}
	if v, ok := zSet.dict[member]; ok {
		rank := zSet.skipList.getRank(v.score, member)
		return (zSet.size) - rank + 1, nil
	}

	// rank zero means no rank found
	return 0, _const.ErrKeyNotFound
}

// ZRange retrieves a specific range of elements from a sorted set (ZSet) denoted by a specific key.
// It returns a slice of ZSetValue containing the elements within the specified range (inclusive), and a nil error when successful.