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读读Redis的官网，学第一手的资料：Redid官方文档地址
或者看看书《Redis 深度历险： 核心原理和应用实践》
1、Redis官网中介绍各种数据类型
? 官方地址：Redis data types
Redis is not a plain key-value store, it is actually a data structures server, supporting different kinds of values. What this means is that, while in traditional key-value stores you associate string keys to string values, in Redis the value is not limited to a simple string, but can also hold more complex data structures. The following is the list of all the data structures supported by Redis, which will be covered separately in this tutorial:
- Binary-safe strings.
- Lists: collections of string elements sorted according to the order of insertion. They are basically linked lists.
- Sets: collections of unique, unsorted string elements.
- Sorted sets, similar to Sets but where every string element is associated to a floating number value, called score. The elements are always taken sorted by their score, so unlike Sets it is possible to retrieve a range of elements (for example you may ask: give me the top 10, or the bottom 10).
- Hashes, which are maps composed of fields associated with values. Both the field and the value are strings. This is very similar to Ruby or Python hashes.
- Bit arrays (or simply bitmaps): it is possible, using special commands, to handle String values like an array of bits: you can set and clear individual bits, count all the bits set to 1, find the first set or unset bit, and so forth.
- HyperLogLogs: this is a probabilistic data structure which is used in order to estimate the cardinality of a set. Don't be scared, it is simpler than it seems... See later in the HyperLogLog section of this tutorial.
- Streams: append-only collections of map-like entries that provide an abstract log data type. They are covered in depth in the Introduction to Redis Streams.
2、各种数据类型适合在什么场合使用呢？
2.1 Strings 简单的KV缓存
> set mykey somevalue
OK
> get mykey
"somevalue"
2.2 Lists 有序列表
文章的评论列表，可以通过 lrange 命令分页，读取某个闭区间内的元素，可以基于 list 实现分页查询，这个是很棒的一 个功能，基于 redis 实现简单的高性能分页，可以做类似微博那种下拉不断分页的东西，性能高
> rpush mylist A
(integer) 1
> rpush mylist B
(integer) 2
> lpush mylist first
(integer) 3
> lrange mylist 0 -1
1) "first"
2) "A"
3) "B"
2.3 Sets 无需集合，自动去重。
如果你需要对一些数据进行快速的全局 去重，你当然也可以基于 jvm 内存里的 HashSet 进行去重，但是如果你的某个系统部署在多台机器上呢？ 得基于 redis 进行全局的 set 去重。可以基于Redis的Sets玩集合的交集、并集、差集等。
> sadd myset 1 2 3
(integer) 3
> smembers myset
1. 3
2. 1
3. 2
2.4 Sorted Sets 是排序的set，去重但可以排序，写进去的时候给一个分数，自动根据分数排序。
适用于排行榜：有序集合经典使用场景。例如视频网站需要对用户上传的视频做排行榜，榜单维护可能是多方面：按照时间、按照播放量、按照获得的赞数等。
> zadd hackers 1940 "Alan Kay"
(integer) 1
> zadd hackers 1957 "Sophie Wilson"
(integer) 1
> zadd hackers 1953 "Richard Stallman"
(integer) 1
> zadd hackers 1949 "Anita Borg"
(integer) 1
> zadd hackers 1965 "Yukihiro Matsumoto"
(integer) 1
> zadd hackers 1914 "Hedy Lamarr"
(integer) 1
> zadd hackers 1916 "Claude Shannon"
(integer) 1
> zadd hackers 1969 "Linus Torvalds"
(integer) 1
> zadd hackers 1912 "Alan Turing"
(integer) 1
> zrange hackers 0 -1
1) "Alan Turing"
2) "Hedy Lamarr"
3) "Claude Shannon"
4) "Alan Kay"
5) "Anita Borg"
6) "Richard Stallman"
7) "Sophie Wilson"
8) "Yukihiro Matsumoto"
9) "Linus Torvalds"
2.5 Hashes 这个是类似 map 的一种结构
这个一般就是可以将结构化的数据，比如一个对象（前提是这个对象没嵌套 其他的对象）给缓存在 redis 里，然后每次读写缓存的时候，可以就操作 hash 里的某个字段。比如存储用户信息的场合
> hmset user:1000 username antirez birthyear 1977 verified 1
OK
> hget user:1000 username
"antirez"
> hget user:1000 birthyear
"1977"
> hgetall user:1000
1) "username"
2) "antirez"
3) "birthyear"
4) "1977"
5) "verified"
6) "1"
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