🌙 String类型
https://redis.io/docs/data-types/strings/
String类型，即字符串类型，是Redis中最简单的存储类型。
其value是字符串，不过根据字符串的格式不同，又可以分为3类：
string: 普通字符串int: 整数类型，可以做自增、自减操作float: 浮点类型，可以做自增、自减操作
| KEY | VALUE |
|---|---|
| msg | hello redis |
| num | 10 |
| score | 99.5 |
String 常见命令有：
SET: 添加或者修改已经存在的一个string的键值对GET: 根据key获取String类型的valueMSET: 批量添加多个String类型的valueMGET: 根据多个key获取多个String类型的valueINCR: 让一个整型的key自增1INCRBY: 让一个整型的key自增并制定步长，例如：incrby num 2让num值自增2INCRBYFLOAT: 让一个浮点型的数字自增并指定步长SETNX: 添加一个string类型的键值对，前提是这个key不存在，否则不执行SETEX: 添加一个string类型的键值对，并制定有效期
127.0.0.1:6379> set name jeek
127.0.0.1:6379> get name
"jeek"
127.0.0.1:6379> 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
BITFIELD key [GET type offset] [SET type offset value] [INCRBY type offset increment] [OVERFLOW WRAP|SAT|FAIL]
summary: Perform arbitrary bitfield integer operations on strings
since: 3.2.0
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 [expiration 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
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