ZCARD

ZCARD

返回有序集合中成员数量。当key不存在时，返回0

Command

$ redis-cli -h 127.0.0.1 -p 6379
127.0.0.1:6379> zadd animal 1 cat 2 dog 3 fish
(integer) 3
127.0.0.1:6379> EXISTS fakeSortedSetKey
(integer) 0
127.0.0.1:6379> zcard fakeSortedSetKey
(integer) 0

Code

func zcard(c redis.Conn) {
    defer c.Do("DEL", "animal")
    c.Do("ZADD", "animal", 1, "cat", 2, "dog", 3, "fish")
    countAllMembers, err := redis.Int(c.Do("ZCARD", "animal"))
    if err != nil {
        colorlog.Error(err.Error())
        return
    }
    fmt.Println("The number of all members is:", countAllMembers)
    //  If key doesn't exist, returns 0
    isExist, _ := c.Do("EXISTS", "fakeSortedSetKey")
    if isExist == 1 {
        c.Do("DEL", "fakeSortedSetKey")
    }
    countAllMembers, err = redis.Int(c.Do("ZCARD", "fakeSortedSetKey"))
    if err != nil {
        colorlog.Error(err.Error())
        return
    }
    fmt.Println("The number of all members of fake key is:", countAllMembers)
}

Output

$ go run main.go
The number of all members is: 3
The number of all members of fake key is: 0