Recently, I created a best-selling product list. The goal is to combine the sales volume and sales volume of the product to comprehensively calculate a score, and then rank the best-selling products.
初始化热销榜
对set集合k1进行赋值：
zadd k1 1 a 2 b 3 c 4 d
(integer) 4
1 The first is the list of best-selling products (descending order of best-selling products)
zrevrange k1 0 -1
1) "c"
2) "b"
3) "a"
4) "d"
2 If the product is out of stock, it will not participate in the best-seller ranking
移除集合k1里的元素d
zrem k1 d
(integer) 1
3 Get the best-selling list details
zrange k1 0 -1
1) "a"
2) "b"
3) "c"
如果想获取商品综合分数
zrange k1 0 -1 withscores
1) "a"
2) "1"
3) "b"
4) "2"
5) "c"
6) "3"
4. Can obtain the ranking of the product in the list.
逆向，倒序取排名，索引位置从0开始：
zrevrank k1 a
(integer) 3
The selection data structure is zset in redis. In addition to the above four requirements, it can also perform filtering and automatic sorting.
是可以进行滤重的,通过结果可以看出：eg:
zadd k1 1 a 2 b 3 c
(integer) 0
`redis集合会按分数默认做好了排序，通过获取值即可看出 eg:
正向查询集合k1里的元素的位置：
zrank k1 c
(integer) 2
zrank k1 a
(integer) 0
Extension:
If you need to obtain the score during work, you can use the following command
查询集合k1的元素分数，即score：
zscore k1 a
"1"
zscore k1 c
"3"
>= 2.4: Accepts multiple members. Before Redis 2.4, the command could only add or update one member.