Redis String类型的常见命令

落日映苍穹つ 2023-09-28 08:35 100阅读 0赞

[Ptw-cwl][]

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#### SET：添加或者修改已经存在的一个String类型的键值对 ####

127.0.0.1:6379> help set
    
      SET key value [EX seconds|PX milliseconds|EXAT timestamp|PXAT milliseconds-timestamp|KEEPTTL] [NX|XX] [GET]
      summary: Set the string value of a key
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

添加一个key为name，value为张三的键值对

127.0.0.1:6379> set name zhangsan
    OK
    127.0.0.1:6379> get name
    "zhangsan"
    127.0.0.1:6379>

修改name的值为lisi

127.0.0.1:6379> set name lisi
    OK
    127.0.0.1:6379> get name
    "lisi"
    127.0.0.1:6379>

#### GET：根据key获取String类型的value ####

127.0.0.1:6379> help get
    
      GET key
      summary: Get the value of a key
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

查看name的值

127.0.0.1:6379> get name
    "lisi"
    127.0.0.1:6379>

**注意：如果获取的key不存在，则会返回(nil)，也就是空的意思**

#### MSET：批量添加多个String类型的键值对 ####

127.0.0.1:6379> help mset
    
      MSET key value [key value ...]
      summary: Set multiple keys to multiple values
      since: 1.0.1
      group: string
    
    127.0.0.1:6379>

**示例：**

创建a1 01，a2 02，a3 03 三个键值对

127.0.0.1:6379> mset a1 01 a2 02 a3 03
    OK
    127.0.0.1:6379> mget a1 a2 a3
    1) "01"
    2) "02"
    3) "03"
    127.0.0.1:6379>

修改a1 ，a2 ，a3的值为001,002,003

127.0.0.1:6379> mset a1 001 a2 002 a3 003
    OK
    127.0.0.1:6379> mget a1 a2 a3
    1) "001"
    2) "002"
    3) "003"
    127.0.0.1:6379>

#### MGET：根据多个key获取多个String类型的value ####

127.0.0.1:6379> help mget
    
      MGET key [key ...]
      summary: Get the values of all the given keys
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

获取a1，a2，a3的值

127.0.0.1:6379> mget a1 a2 a3
    1) "001"
    2) "002"
    3) "003"
    127.0.0.1:6379>

#### INCR：让一个整型的key自增1 ####

127.0.0.1:6379> help INCR
    
      INCR key
      summary: Increment the integer value of a key by one
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

让age从15自增到18

127.0.0.1:6379> set age 15
    OK
    127.0.0.1:6379> incr age
    (integer) 16
    127.0.0.1:6379> incr age
    (integer) 17
    127.0.0.1:6379> incr age
    (integer) 18
    127.0.0.1:6379>

#### INCRBY:让一个整型的key自增并指定步长 ####

127.0.0.1:6379> help INCRBY
    
      INCRBY key increment
      summary: Increment the integer value of a key by the given amount
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

让age从18自增到15

127.0.0.1:6379> get age
    "18"
    127.0.0.1:6379> INCRBY age -3
    (integer) 15
    127.0.0.1:6379>

让age从15自增到18

127.0.0.1:6379> get age
    "15"
    127.0.0.1:6379> INCRBY age 3
    (integer) 18
    127.0.0.1:6379>

#### INCRBYFLOAT：让一个浮点类型的数字自增并指定步长 ####

127.0.0.1:6379> help INCRBYFLOAT
    
      INCRBYFLOAT key increment
      summary: Increment the float value of a key by the given amount
      since: 2.6.0
      group: string
    
    127.0.0.1:6379>

**示例：**

让num从5.5自增到9.5

127.0.0.1:6379> set num 5.5
    OK
    127.0.0.1:6379> INCRBYFLOAT num 4
    "9.5"
    127.0.0.1:6379>

让num从9.5自增到10

127.0.0.1:6379> get num
    "9.5"
    127.0.0.1:6379> INCRBYFLOAT num 0.5
    "10"
    127.0.0.1:6379>

#### 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 ####

**注意：如果key存在则不添加，不存在则添加**

127.0.0.1:6379> help SETNX
    
      SETNX key value
      summary: Set the value of a key, only if the key does not exist
      since: 1.0.0
      group: string
    
    127.0.0.1:6379>

示例：

存在key name，不存在name1，分别分别进行添加（key存在则不添加，不存在则添加）

127.0.0.1:6379> get name
    "lisi"
    127.0.0.1:6379> get name1
    (nil)
    127.0.0.1:6379> SETNX name zhangsan
    (integer) 0
    127.0.0.1:6379> SETNX name1 zhangsan
    (integer) 1
    127.0.0.1:6379>

注意：(nil)代表空，0代表添加失败，1代表成功添加一条数据

#### SETEX：添加一个String类型的键值对，并且指定有效期（有效期的单位是秒） ####

127.0.0.1:6379> help SETEX
    
      SETEX key seconds value
      summary: Set the value and expiration of a key
      since: 2.0.0
      group: string
    
    127.0.0.1:6379>

**示例：**

创建一个s1 wangwu键值对，设置有效期为10秒

127.0.0.1:6379> SETEX s1 10 wangwu
    OK
    127.0.0.1:6379> get s1
    "wangwu"
    127.0.0.1:6379> ttl s1
    (integer) 3
    127.0.0.1:6379> ttl s1
    (integer) 1
    127.0.0.1:6379> ttl s1
    (integer) 0
    127.0.0.1:6379> ttl s1
    (integer) -2
    127.0.0.1:6379> get s1
    (nil)
    127.0.0.1:6379>

[Ptw-cwl][]

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[Ptw-cwl]: https://blog.csdn.net/qq_62701769