Redis教程（6）
5）sorted sets
和set一样sorted set也是string类型元素的集合，不同的是每个元素都会关联一个double类型的score。sorted set的实现是skip list和hash table的混合体。
当元素被添加到集合中时，一个元素到score的映射被添加到hash table中，所以给定一个元素获取score的开销是O(1),另一个score到元素的映射被添加到skip list，并按照score排序，所以就可以有序的获取集合中的元素。添加，删除操作开销都是O(log(N))和skip list的开销一致,redis的skip list实现用的是双向链表,这样就可以逆序从尾部取元素。sorted set最经常的使用方式应该是作为索引来使用.我们可以把要排序的字段作为score存储，对象的id当元素存储。下面是sorted set相关命令
1、zadd
向名称为key的zset中添加元素member，score用于排序。如果该元素已经存在，则根据score更新该元素的顺序
redis
127.0
.
0.1
:
6379
>
zadd myzset
1
"
one
"
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset 2 " two "
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset 3 " two "
( integer ) 0
redis 127.0 . 0.1 : 6379 > zrange myzset 0 - 1 withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset 2 " two "
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset 3 " two "
( integer ) 0
redis 127.0 . 0.1 : 6379 > zrange myzset 0 - 1 withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
本例中我们向myzset中添加了one和two，并且two被设置了2次，那么将以最后一次的设置为准，最后我们将所有元素都显示出来并显示出了元素的score。
2、zrem
删除名称为key的zset中的元素member
redis
127.0
.
0.1
:
6379
>
zrange myzset
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 > zrem myzset two
( integer ) 1
redis 127.0 . 0.1 : 6379 > zrange myzset 0 - 1 withscores
1 ) " one "
2 ) " 1 "
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 > zrem myzset two
( integer ) 1
redis 127.0 . 0.1 : 6379 > zrange myzset 0 - 1 withscores
1 ) " one "
2 ) " 1 "
redis 127.0 . 0.1 : 6379 >
可以看到two被删除了
3、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increment;否则向集合中添加该元素，其score的值为increment
redis
127.0
.
0.1
:
6379
>
zadd myzset2
1
"
one
"
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset2 2 " two "
( integer ) 1
redis 127.0 . 0.1 : 6379 > zincrby myzset2 2 " one "
" 3 "
redis 127.0 . 0.1 : 6379 > zrange myzset2 0 - 1 withscores
1 ) " two "
2 ) " 2 "
3 ) " one "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
( integer ) 1
redis 127.0 . 0.1 : 6379 > zadd myzset2 2 " two "
( integer ) 1
redis 127.0 . 0.1 : 6379 > zincrby myzset2 2 " one "
" 3 "
redis 127.0 . 0.1 : 6379 > zrange myzset2 0 - 1 withscores
1 ) " two "
2 ) " 2 "
3 ) " one "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
本例中将one的score从1增加了2，增加到了3
4、zrank
返回名称为key的zset中member元素的排名(按score从小到大排序)即下标
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrank myzset3 two
( integer ) 1
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrank myzset3 two
( integer ) 1
redis 127.0 . 0.1 : 6379 >
本例中将two的下标是1，我这里取的是下标，而不是score
5、zrevrank
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
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrank myzset3 two
( integer ) 1
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrank myzset3 two
( integer ) 1
redis 127.0 . 0.1 : 6379 >
按从大到小排序的话two是第三个元素，下标是2
6、zrevrange
返回名称为key的zset(按score从大到小排序)中的index从start到end的所有元素
redis
127.0
.
0.1
:
6379
>
zrevrange myzset3
0
-
1
withscores
1 ) " five "
2 ) " 5 "
3 ) " three "
4 ) " 3 "
5 ) " two "
6 ) " 2 "
7 ) " one "
8 ) " 1 "
redis 127.0 . 0.1 : 6379 >
1 ) " five "
2 ) " 5 "
3 ) " three "
4 ) " 3 "
5 ) " two "
6 ) " 2 "
7 ) " one "
8 ) " 1 "
redis 127.0 . 0.1 : 6379 >
首先按score从大到小排序，再取出全部元素
7、zrangebyscore
返回集合中score在给定区间的元素
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrangebyscore myzset3 2 3 withscores
1 ) " two "
2 ) " 2 "
3 ) " three "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zrangebyscore myzset3 2 3 withscores
1 ) " two "
2 ) " 2 "
3 ) " three "
4 ) " 3 "
redis 127.0 . 0.1 : 6379 >
本例中，返回了score在2~3区间的元素
8、zcount
返回集合中score在给定区间的数量
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zcount myzset3 2 3
( integer ) 2
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zcount myzset3 2 3
( integer ) 2
redis 127.0 . 0.1 : 6379 >
本例中，计算了score在2~3之间的元素数目
9、zcard
返回集合中元素个数
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zcard myzset3
( integer ) 4
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zcard myzset3
( integer ) 4
redis 127.0 . 0.1 : 6379 >
从本例看出myzset3这个集全的元素数量是4
10、zscore
返回给定元素对应的score
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zscore myzset3 two
" 2 "
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zscore myzset3 two
" 2 "
redis 127.0 . 0.1 : 6379 >
此例中我们成功的将two的score取出来了。
11、zremrangebyrank
删除集合中排名在给定区间的元素
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zremrangebyrank myzset3 3 3
( integer ) 1
redis 127.0 . 0.1 : 6379 > zrange myzset3 0 - 1 withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
7 ) " five "
8 ) " 5 "
redis 127.0 . 0.1 : 6379 > zremrangebyrank myzset3 3 3
( integer ) 1
redis 127.0 . 0.1 : 6379 > zrange myzset3 0 - 1 withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
redis 127.0 . 0.1 : 6379 >
在本例中我们将myzset3中按从小到大排序结果的下标为3的元素删除了。
12、zremrangebyscore
删除集合中score在给定区间的元素
redis
127.0
.
0.1
:
6379
>
zrange myzset3
0
-
1
withscores
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
redis 127.0 . 0.1 : 6379 > zremrangebyscore myzset3 1 2
( integer ) 2
redis 127.0 . 0.1 : 6379 > zrange myzset3 0 - 1 withscores
1 ) " three "
2 ) " 3 "
redis 127.0 . 0.1 : 6379 >
1 ) " one "
2 ) " 1 "
3 ) " two "
4 ) " 2 "
5 ) " three "
6 ) " 3 "
redis 127.0 . 0.1 : 6379 > zremrangebyscore myzset3 1 2
( integer ) 2
redis 127.0 . 0.1 : 6379 > zrange myzset3 0 - 1 withscores
1 ) " three "
2 ) " 3 "
redis 127.0 . 0.1 : 6379 >
在本例中我们将myzset3中按从小到大排序结果的score在1~2之间的元素删除了。