Redis (2): String common commands for data structure

1、set/get

127.0.0.1:6379> set name ermu
OK
127.0.0.1:6379> get name
"ermu"
127.0.0.1:6379> get notexitkey
(nil)

2. mget obtains the value of multiple keys in batch

127.0.0.1:6379> mget name notexitkey
1) "ermu"
2) (nil)

3. incr && incrby only +1 the integer value incr to the value corresponding to the key; incrby plus the specified value  

127.0.0.1:6379> get age
"22"
127.0.0.1:6379> incr age
(integer) 23
127.0.0.1:6379> get age
"23"
127.0.0.1:6379> incrby age 20
(integer) 43
127.0.0.1:6379> incr name
(error) ERR value is not an integer or out of range

4、decr && decrby

127.0.0.1:6379> decr age 
(integer) 42
127.0.0.1:6379> decrby age 20
(integer) 22

5. Setnx returns 0 if the key already exists

127.0.0.1:6379> setnx height 170
(integer) 1
127.0.0.1:6379> setnx height 172
(integer) 0
127.0.0.1:6379> get height
"170"

6, setex set expire unit second 

127.0.0.1:6379> setex exkey1 5 value1
OK
127.0.0.1:6379> get exkey1
"value1"
# 五秒后再次获取
127.0.0.1:6379> get exkey1
(nil)

7 、 getrange

127.0.0.1:6379> set selfinfo "Hellow World !"
OK
127.0.0.1:6379> getrange selfinfo 0 -1
"Hellow World !"
# -1则表示后面所有
127.0.0.1:6379> getrange selfinfo 1 3
"ell"

8.append

127.0.0.1:6379> append selfinfo ermu
(integer) 18
127.0.0.1:6379> get selfinfo
"Hellow World !ermu"