ZSCAN

ZSCAN

用于迭代有序集合中的元素（包括元素成员和元素分值）

ZSCAN key cursor [MATCH pattern] [COUNT count]

最后的那个COUNT，当有序集合中成员较多时用得上。下面示例中的有序集合的成员很少，所以一次性scan出来。当成员较多时，不会一次性将scan的结果显示出来，这时就需要使用COUNT加大显示的结果的数量。

Command

127.0.0.1:6379> ZADD vehicle 0 benz 1 audi 2 chrysler 3 bmw
(integer) 4
127.0.0.1:6379> ZSCAN vehicle 0
1) "0"
2) 1) "benz"
   2) "0"
   3) "audi"
   4) "1"
   5) "chrysler"
   6) "2"
   7) "bmw"
   8) "3"
127.0.0.1:6379> ZSCAN vehicle 0 MATCH b*
1) "0"
2) 1) "benz"
   2) "0"
   3) "bmw"
   4) "3"

Code

此处忽略了错误处理，比如redis.Scan的错误处理

func zscan(c redis.Conn) {
    defer c.Do("DEL", "vehicle")
    c.Do("ZADD", "vehicle", 0, "bmw", 1, "audi", 2, "chrysler", 3, "bmw")
    zscanResult, _ := redis.Values(c.Do("ZSCAN", "vehicle", 0))
    var cursor int
    var membersAndScores []string
    redis.Scan(zscanResult, &cursor, &membersAndScores)
    fmt.Println("The new cursor is:", cursor)
    for i, v := range membersAndScores {
        if i%2 == 0 {
            fmt.Println("Member", i/2, "is:", v)
        } else {
            fmt.Println("Score of member", (i-1)/2, "is:", v)
        }
    }
}

Output

$ go run main.go 
The new cursor is: 0
Member 0 is: audi      
Score of member 0 is: 1
Member 1 is: chrysler  
Score of member 1 is: 2
Member 2 is: bmw       
Score of member 2 is: 3