Redis数据类型
官网说明文档：http://www.redis.io/topics/data-types-intro
Redis keys
Redis keys are binary safe, this means that you can use any binary sequence as a key, from a string like "foo" to the content of a JPEG file. The empty string is also a valid key.
Redis key是二进制安全的，这意味着你可以使用任何二进制序列作为一个key，从一个字符串”foo”到JPEG文件的内容。空字符串也是合法的key。
规则
- Key不要太长，消耗内存，在数据集中查找key可能会需要更多的匹配成本。
- Key不要太短，可读性较差，
- 追寻一种模式"object-type:id" "comment:1234:reply.to" or "comment:1234:reply-to"
- Key允许的最大值为512M
Redis客户端 Redis-Cli
查看帮助
redis-cli --help
指定数据块编号
redis-cli -n 0
获取命令的帮助信息
官网帮助文档：http://www.redis.io/commands
help @string 获取数据类型string的相关操作命令
help @list 获取数据类型list的相关操作命令
help set
help <tab>键 有提示信息
String
一个字符串类型的值最多能存储512M字节的内容
这里简单介绍下String类型：
help @string
APPEND key value summary: Append a value to a key since: 2.0.0 BITCOUNT key [start] [end] summary: Count set bits in a string since: 2.6.0 BITOP operation destkey key [key ...] summary: Perform bitwise operations between strings since: 2.6.0 BITPOS key bit [start] [end] summary: Find first bit set or clear in a string since: 2.8.7 DECR key summary: Decrement the integer value of a key by one since: 1.0.0 DECRBY key decrement summary: Decrement the integer value of a key by the given number since: 1.0.0 GET key summary: Get the value of a key since: 1.0.0 GETBIT key offset summary: Returns the bit value at offset in the string value stored at key since: 2.2.0 GETRANGE key start end summary: Get a substring of the string stored at a key since: 2.4.0 GETSET key value summary: Set the string value of a key and return its old value since: 1.0.0 INCR key summary: Increment the integer value of a key by one since: 1.0.0 INCRBY key increment summary: Increment the integer value of a key by the given amount since: 1.0.0 INCRBYFLOAT key increment summary: Increment the float value of a key by the given amount since: 2.6.0 MGET key [key ...] summary: Get the values of all the given keys since: 1.0.0 MSET key value [key value ...] summary: Set multiple keys to multiple values since: 1.0.1 MSETNX key value [key value ...] summary: Set multiple keys to multiple values, only if none of the keys exist since: 1.0.1 PSETEX key milliseconds value summary: Set the value and expiration in milliseconds of a key since: 2.6.0 SET key value [EX seconds] [PX milliseconds] [NX|XX] summary: Set the string value of a key since: 1.0.0 SETBIT key offset value summary: Sets or clears the bit at offset in the string value stored at key since: 2.2.0 SETEX key seconds value summary: Set the value and expiration of a key since: 2.0.0 SETNX key value summary: Set the value of a key, only if the key does not exist since: 1.0.0 SETRANGE key offset value summary: Overwrite part of a string at key starting at the specified offset since: 2.2.0 STRLEN key summary: Get the length of the value stored in a key since: 2.2.0
设置Key-value值
SET key value [EX seconds] [PX milliseconds] [NX|XX]
EX 过期时间，秒 等同于 SETEX key seconds value
PX 过期时间，毫秒 等同于 PSETEX key milliseconds value
NX 键不存在，才能设置 等同于 SETNX key value
XX 键存在时，才能设置
设置多个Key和value
MSET key value [key value ...]
MSETNX key value [key value ...] 键不存在时，才设置值
过期设置
设置多少秒或毫秒后过期
EXPIRE key seconds 秒
PEXPIRE key milliseconds 毫秒
设置在指定unix时间戳过期
EXPIREAT key timestamp 秒
PEXPIREAT key milliseconds-timestamp 毫秒
PERSIST key 删除过期的key
查看剩余时间
TTL key
PTTL key
-1 没有设置TTL
-2找有找到key
查找key
KEYS pattern
*任意长度字符
？任意一个字符
[]字符集合
增量计数
INCR key
例子：
set counter 100
INCR counter
101
INCRBY key increment 根据给定的值进行增量计数
DECR key
DECRBY key increment
设置位值
SETBIT key offset value
offset偏移从0开始
value值为0或1
获取位置
GETBIT key offset
位所在位置
BITPOS key bit [start] [end]
start 值从0开始，偏移量为字节，不是位
bit值为0或者1
统计指定区间上值为1的个数
BITCOUNT key [start] [end]
start 值从0开始，偏移量为字节，不是位
返回1的个数
可以合理利用BIT操作来进行数据的统计
按天统计网站活跃用户
日期作为key,用户ID作为offset,上线置位1
求一段时间内活跃用户数
SETBIT 20160802 13 1 用户在哪天有上线记录 SETBIT 20160801 12 1 SETBIT 20160803 12 1
BITOP OR 20160801-3 20160801 20160802 20160803 这期间有哪些用户有上线记录，针对重复的不进行累计，只做记录
BITCOUNT 20160801-3 获得统计结果，有多少用户在这期间登录过
