Type: String¶
String is a basic type on Redis
The maximum capcity of type String is 512M Byte.
In type String, you can use the text as the string value. That is normal.
But the String in Redis can be calculate if the string content is numeric.
You can add or subtract a integer string by command INCR, INCRBY, DECR, DECRBY.
And you can add a floating string by command INCRBYFLOAT and positive argument, subtract by command INCRBYFLOAT and nagetive argument.
In addition, you can also do binary manipulation on strings with command SETBIT, GETBIT, BITCOUNT, BITOP, BITPOS...
| command | syntax | description | example | return |
|---|---|---|---|---|
| set | SET key value |
set a pair of key-value | set name boii |
OK |
| get | GET key |
get the value of key | get name |
"boii" |
| mset | MSET key value [key value ...] |
set more pair of key-value at one time | mset name boii age 18 |
OK |
| mget | MGET key [key ...] |
get more values of key-value at one time | mget name age |
"boii" "18" |
| setex | SETEX key seconds value |
shortcut of SET key value + EXPIRE key seconds |
setex name 5 boii |
OK |
| psetex | PSETEX key seconds value |
shortcur of SET key value + PEXPIRE key microseconds |
psetex name 5000 boii |
OK |
| setnx | SETNX key value |
set a pair of key-value if key isn't exists | setnx name boii |
1 if successful, otherwise 0 |
| msetnx | SETNX key value [key value ...] |
set more pair of key-value if all key isn't exists | msetnx name boii age 18 |
1 if all key isn't exists, otherwise 0 |
| getset | GETSET key newValue |
get the value of key and set the new value | getset name eva |
"boii" |
| strlen | SETLEN key |
return the length of key's value | strlen name |
4 |
| append | APPEND key value |
append the new value after the value of key | append name good |
8 |
| getrange | GETRANGE key start end |
similar to slice but include end character, -1 means until the end | getrange name 0 5 |
"boiigo" |
| decr | DECR key |
decrease one from a numeric value, similar key-- |
decr age |
17 |
| decrby | DECRBY key decrement |
similar key -= decrement |
decrby age 10 |
7 |
| incr | INCR key |
increase one from a numeric value, similar key++ |
incr age |
8 |
| incrby | INCRBY key increment |
similar key += increment |
incrby age 100 |
108 |
| incrbyfloat | INCRBYFLOAT key increment |
increase a float value to a numeric value, Maximum 17 decimal places | incrbyfloat age 0.5 |
108.5 |