set [key] [value]
设定给定key的值,如果key已存在则会覆盖,并且无视类型
- Redis 2.6.12 以前的版本,set命令总是返回 OK
- Redis 2.6.12 版本开始,只有设置成功时才会返回 OK
# key不存在
127.0.0.1:6379> exists set-key
(integer) 0
127.0.0.1:6379> set set-key 1
OK
# key已存在且为其他类型
127.0.0.1:6379> lpush exists-list-key a
(integer) 1
127.0.0.1:6379> lpush exists-list-key b
(integer) 2
127.0.0.1:6379> lpush exists-list-key c
(integer) 3
127.0.0.1:6379> exists exists-list-key
(integer) 1
127.0.0.1:6379> type exists-list-key
list
127.0.0.1:6379> set exists-list-key 1
OK
127.0.0.1:6379> type exists-list-key
string
127.0.0.1:6379> get exists-list-key
"1"
get [key]
获取给定key的值
- 如果key不存在,则返回nil
- 如果key储存的值不是string,则返回一个错误
# 正常情况
127.0.0.1:6379> set get-key 1
OK
127.0.0.1:6379> get get-key
"1"
# key不存在
127.0.0.1:6379> exists unexists-key
(integer) 0
127.0.0.1:6379> get unexists-key
(integer) nil
# key储存的值不是string类型
127.0.0.1:6379> lpush list-key a
(integer) 1
127.0.0.1:6379> get list-key
(error) WRONGTYPE Operation against a key holding the wrong kind of value
getrange [key] [start] [end]
获取存储在指定key 中字符串的子字符串。字符串的截取范围由start和 end两个偏移量决定(包括start和end在内)
127.0.0.1:6379> set getrange-key helloredis
OK
127.0.0.1:6379> getrange getrange-key 3 7
"lored"
127.0.0.1:6379> getrange getrange-key 3 30
"loredis"
127.0.0.1:6379> getrange getrange-key -2 30
"is"
setrange [key] [offset] [value]
用指定的字符串覆盖给定key所储存的字符串,覆盖的位置从偏移量offset开始,返回被修改后的字符串的长度
127.0.0.1:6379> set setrange-key helloredis
OK
127.0.0.1:6379> setrange setrange-key 3 tt
(integer) 10
127.0.0.1:6379> get setrange-key
"helttredis"
getset [key] [value]
设置key的值并返回旧值,如果key不存在,则返回nil,并设置key的值
# key存在
127.0.0.1:6379> set getset-key 111
OK
127.0.0.1:6379> getset getset-key 222
"111"
127.0.0.1:6379> get getset-key
"222
# key不存在
127.0.0.1:6379> exists unexists-getset-key
(integer) 0
127.0.0.1:6379> getset unexists-getset-key 1
(nil)
127.0.0.1:6379> get unexists-getset-key
"1"
getbit [key] [offset]
对给定key所存储的字符串值,获取指定偏移量上的位(bit),当偏移量offset比字符串值的长度大或者key不存在时返回0.
# 正常情况
127.0.0.1:6379> getbit setbit-key 10086
(integer) 1
# key不存在
127.0.0.1:6379> getbit unexists-key 100
(integer) 0
# 偏移量offset比字符串值的长度大
127.0.0.1:6379> getbit setbit-key 100000
(integer) 0
setbit [key] [offset] [bit]
对给定key所存储的字符串值,设置或清除指定偏移量上的位(bit)
127.0.0.1:6379> setbit setbit-key 10086 1
(integer) 0
127.0.0.1:6379> getbit setbit-key 10086
(integer) 1
127.0.0.1:6379> getbit setbit-key 100
(integer) 0
mget [key1] [key2] … [keyn]
返回一个或多个给定key的值,如果其中某个key不存在,则这个key返回nil
127.0.0.1:6379> set mget-key 1
OK
127.0.0.1:6379> set mget-key2 2
OK
127.0.0.1:6379> set mget-key3 3
OK
127.0.0.1:6379> mget mget-key mget-key2 mget-key3 mget-key4
1) "1"
2) "2"
3) "3"
4) (nil)
mset [key1] [value1] [key2] [value2] … [keyn] [valuen]
同时设置一个或多个key
127.0.0.1:6379> mset mset-key 1 mset-key2 2 mset-key3 3
OK
127.0.0.1:6379> mget mset-key mset-key2 mset-key3
1) "1"
2) "2"
3) "3"
msetnx [key1] [value1] [key2] [value2] … [keyn] [valuen]
同时设置一个或多个key,当所有key都不存在时,才会成功返回1,有一个key存在就会失败返回0,并且其它不存在的key也不会赋值(原子性)
127.0.0.1:6379> set msetnx-key 222
OK
127.0.0.1:6379> msetnx msetnx-key 1 msetnx-key2 2 msetnx-key3 3
(integer) 0
127.0.0.1:6379> mget msetnx-key msetnx-key2 msetnx-key3
1) "222"
2) (nil)
3) (nil)
setex [key] [timeout] [value]
为指定key设置值及过期时间,如果key已存在,则覆盖旧值
如果timeout<=0,则返回一个错误
# 正常情况
127.0.0.1:6379> set setex-key 1
OK
127.0.0.1:6379> setex setex-key 20 2
OK
127.0.0.1:6379> ttl setex-key
(integer) 18
127.0.0.1:6379> get setex-key
"2"
# timeout<=0
127.0.0.1:6379> set setex-key 1
OK
127.0.0.1:6379> setex setex-key 0 1
(error) ERR invalid expire time in setex
127.0.0.1:6379> setex setex-key -1 1
(error) ERR invalid expire time in setex
psetex [key] [timeout] [value]
作用于setex类似,区别在于过期时间戳以毫秒为单位
如果timeout<=0,则返回一个错误
# 正常情况
127.0.0.1:6379> set psetex-key 1
OK
127.0.0.1:6379> psetex psetex-key 20000 2
OK
127.0.0.1:6379> pttl psetex-key
(integer) 16063
127.0.0.1:6379> get psetex-key
"2"
# timeout<=0
127.0.0.1:6379> set psetex-key 1
OK
127.0.0.1:6379> psetex psetex-key 0 2
(error) ERR invalid expire time in psetex
127.0.0.1:6379> psetex psetex-key -1 2
(error) ERR invalid expire time in psetex
setnx [key] [value]
当给定key不存在时,为key设置给定值,如果key已存在,则不覆盖
# 正常情况
127.0.0.1:6379> exists setnx-key
(integer) 0
127.0.0.1:6379> setnx setnx-key 1
(integer) 1
# key已存在
127.0.0.1:6379> set exists-key 1
OK
127.0.0.1:6379> setnx exists-key 2
(integer) 0
127.0.0.1:6379> get exists-key
"1"
strlen [key]
返回给定key所储存的字符串的长度
- 给定key储存的不是字符串时返回一个错误
- 给定key不存在时返回0
# 正常情况
127.0.0.1:6379> set strlen-key helloredis
OK
127.0.0.1:6379> strlen strlen-key
(integer) 10
# 给定key储存的不是字符串
127.0.0.1:6379> lpush list-key2 111
(integer) 1
127.0.0.1:6379> strlen list-key2
(error) WRONGTYPE Operation against a key holding the wrong kind of value
# 给定key不存在
127.0.0.1:6379> exists unexists-key
(integer) 0
127.0.0.1:6379> strlen unexists-key
(integer) 0
incr [key]
将给定key的值增1,返回增长后的值
- 如果key不存在,则key的值会先被初始化为0,再执行incr操作
- 如果值包含错误类型或字符串类型的值不能表示为数字,则返回一个错误
- 操作的值限定在64位(bit)有符号数字表示之内
# 正常情况
127.0.0.1:6379> set incr-key 1
OK
127.0.0.1:6379> incr incr-key
(integer) 2
127.0.0.1:6379> get incr-key
"2"
# key不存在
127.0.0.1:6379> exists incr-key2
(integer) 0
127.0.0.1:6379> incr incr-key2
(integer) 1
127.0.0.1:6379> get incr-key2
"1"
# key储存的值不是数字
127.0.0.1:6379> set incr-key3 1aa
OK
127.0.0.1:6379> incr incr-key3
(error) ERR value is not an integer or out of range
# key储存的值类型不是字符串
127.0.0.1:6379> lpush incr-key4 1
(integer) 1
127.0.0.1:6379> incr incr-key4
(error) WRONGTYPE Operation against a key holding the wrong kind of value
incrby [key] [increment]
作用于incr类似,区别在于增长的值是increment,increment的值不是数字时,会返回一个错误
# 正常情况
127.0.0.1:6379> set incrby-key 1
OK
127.0.0.1:6379> incrby incrby-key 2
(integer) 3
127.0.0.1:6379> incrby incrby-key -1
(integer) 2
127.0.0.1:6379> incrby incrby-key 0
(integer) 2
# increment不是数字
127.0.0.1:6379> incrby incrby-key a
(error) ERR value is not an integer or out of range
incrbyfloat [key] [increment]
作用于incrby类似,区别在于increment是浮点数,返回的类型是非指数符号格式或者整数
# 正常情况
127.0.0.1:6379> set incrbyfloat-key 0.9
OK
127.0.0.1:6379> incrbyfloat incrbyfloat-key 1.2
"2.1"
# 增长结果转为整型
127.0.0.1:6379> set incrbyfloat-key 0.9
OK
127.0.0.1:6379> incrbyfloat incrbyfloat-key 0.1
"1"
# 指数符号增长后变为非指数格式
127.0.0.1:6379> set incrbyfloat-key2 314e-2
OK
127.0.0.1:6379> get incrbyfloat-key2
"314e-2"
127.0.0.1:6379> incrbyfloat incrbyfloat-key2 0.01
"3.15"
decr [key]
规则与incr类似,区别在于不是增长1,而是减去1
# 正常情况
127.0.0.1:6379> set decr-key 2
OK
127.0.0.1:6379> decr decr-key
(integer) 1
decrby [key] [decrement]
规则与incrby类似,区别在于不是增长,而是减去decrement
127.0.0.1:6379> set decrby-key 10
OK
127.0.0.1:6379> decrby decrby-key 5
(integer) 5
append [key] [value]
为指定的key追加值
- key存在且储存的是字符串时,用value追加
- key不存在时,用value赋值
- key储存的不是string时,返回一个错误
# 正常情况
127.0.0.1:6379> set append-key aaa
OK
127.0.0.1:6379> append append-key bbb
(integer) 6
127.0.0.1:6379> get append-key
"aaabbb"
# key不存在
127.0.0.1:6379> exists append-key2
(integer) 0
127.0.0.1:6379> append append-key2 bbb
(integer) 3
127.0.0.1:6379> get append-key2
"bbb"
# key储存的不是string
127.0.0.1:6379> lpush append-key3 a
(integer) 1
127.0.0.1:6379> append append-key2 bbb
(integer) 6
127.0.0.1:6379> append append-key3 bbb
(error) WRONGTYPE Operation against a key holding the wrong kind of value
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