zset类型以及其操作

sorted set类型

sorted sets类型以及其操作
zset是set的一格升级版本，它在set的基础上增加了一格顺序属性，这一属性在添加元素的同时可以指定，每次指定后，zset会自动重新按照新的值调整顺序。可以理解为有两列的mysql表，一列存储value，一列存储顺序。操作中key理解成zset的名字。

zadd
向名称为key的zset中添加元素member，score用于排序，如果该元素存在，则更新其顺序

127.0.0.1:> zadd key [NX|XX] [CH] [INCR] score member [score member ...]
127.0.0.1:> zadd zset  one
(integer)
127.0.0.1:> zadd zset - two
(integer) 

zrange
遍历集合的元素
127.0.0.1:6379> zrange key start stop [WITHSCORES] //withscores代表的是否显示顺序号  start和stop代表所在的位置的索引。可以这样理解：将集合元素依照顺序值升序排序再输出，start和stop限制遍历的限制范围

127.0.0.1:> zadd zset - hhh
(integer)
127.0.0.1:> zrange zset
) "hhh"。
127.0.0.1:> zrange zset  - withscore
) "two"
) "-1"
) "one"
) ""
zset元素也是不重复的，不要将它理解成为map了，score只是附加的，并不是array中的Index，而是代表该元素的顺序号
同一个顺序可以有多个元素：
127.0.0.1:6379>  zrange zset 0 -1 withscores
1) "one"
2) "0"
3) "two"
4) "0"

zrem
删除集合中的member元素

127.0.0.1:> zrange zset  - withscores
) "one"
) ""
) "two"
) ""
) "three"
) ""
127.0.0.1:> zrem zset one
(integer)
127.0.0.1:> zrange zset  -
) "two"
) "three"

zincrby
如果在名称为key的zset中已经存在元素member，则该元素的score增加incremenr否则向该集合中添加该元素，其score的值为increment

127.0.0.1:> zincrby key increment member
127.0.0.1:> zincrby zset  two
""
127.0.0.1:> zincrby zset  four
""
127.0.0.1:> zrange zset  - withscores
) "four"
) ""
) "three"
) ""
) "two"
) ""
127.0.0.1:>
127.0.0.1:> zincrby zset - two
""

zrank
返回名称为key的zset中member元素的排名（类似索引从0开始）（按score从小到大排序）即下标

127.0.0.1:> zrank key member
127.0.0.1:> zrange zset  - withscores
) "two"
) ""
) "four"
) ""
) "three"
) ""
127.0.0.1:> zrank zset two
(integer)
127.0.0.1:> zrank zset four
(integer)
127.0.0.1:> zrank zset three
(integer) 

注意得到的是排名而不是顺序值score

zrevrank
rev：代表翻转
返回名称为key的zset中member元素的排名（按score从大到小排序），即下标

127.0.0.1:> zrange zset  - withscores
 ) "hhh"
 ) "-1"
 ) "hi"
 ) ""
 ) "two"
 ) ""
 ) "four"
 ) ""
 ) "three"
) ""
127.0.0.1:> zrank zset hhh
(integer)
127.0.0.1:> zrevrank zset hhh
(integer) 

zrevrange
按照顺序值降序排序然后显示指定下标内的值

127.0.0.1:> zrevrange key start stop [WITHSCORES]
127.0.0.1:> zrevrange zset  - withscores
 ) "three"
 ) ""
 ) "four"
 ) ""
 ) "two"
 ) ""
 ) "hi"
 ) ""
 ) "hhh"
) "-1"
127.0.0.1:> zrange zset  - withscores
 ) "hhh"
 ) "-1"
 ) "hi"
 ) ""
 ) "two"
 ) ""
 ) "four"
 ) ""
 ) "three"
) ""

zrangebyscore
就是利用score升序排序，而是返回集合中score给定区间内的元素。范围内的元素一句score升序排序。start和stop代表的不再是index而是score

127.0.0.1:> zrangebyscore key min max [WITHSCORES] [LIMIT offset count]
127.0.0.1:> zrange zset  - withscores
 ) "hhh"
 ) "-1"
 ) "hi"
 ) ""
 ) "two"
 ) ""
 ) "four"
 ) ""
 ) "three"
) ""
127.0.0.1:> zrangebyscore zset -  withscores
) "hhh"
) "-1"
) "hi"
) ""
) "two"
) ""

zcount
返回集合中score指定区间中元素的数量

127.0.0.1:> zcount key min max
127.0.0.1:> zcount zset -
(integer) 

zcard
返回集合中的集合元素

127.0.0.1:> zcard zset
(integer) 

zremrangebyrank
删除集合中排名在指定区间内的元素，排名意思是index，排序值是score

127.0.0.1:> zremrangebyrank key start stop
127.0.0.1:> zrange zset  - withscores
 ) "hhh"
 ) "-1"
 ) "hi"
 ) ""
 ) "two"
 ) ""
 ) "four"
 ) ""
 ) "three"
) ""
127.0.0.1:> zremrangebyrank zset
(integer)
127.0.0.1:> zrange zset  - withscores
) "four"
) ""
) "three"
) ""

remrangebyscore
删除集合中排序值在指定区间的元素

127.0.0.1:> zrangebyscore key min max [WITHSCORES] [LIMIT offset count]
127.0.0.1:> zrange zset  - withscores
) "four"
) ""
) "three"
) ""
127.0.0.1:> zremrangebyscore zset
(integer)
127.0.0.1:> zremrangebyscore zset
(integer)
127.0.0.1:> zrange zset  - withscores
(empty list or set)