Shulou(Shulou.com)06/01 Report--

Redis is the data structure of key-value. Each piece of data is a key-value pair.

The type of key is a string, so no quotation marks are required because the default is a string.

Note: keys cannot be repeated

There are five types of values:

String string

Hash hash

List list

Set set

Ordered set zset

# string string key

Add if the key set by set key value # does not exist, or modify it if the key already exists

Set name daiby

Set key value [NX | XX] # NX: succeed if key does not exist, otherwise fail (do not overwrite the old value)! XX: succeed if key exists, otherwise fail (be sure to overwrite the old value)!

Set aaa 222 nx # failed if aaa exists

Set aaa 222 xx # failed if aaa does not exist

Setnx key value # sets the value of key to value, which is equivalent to set key value nx, only if key does not exist

Msetnx key value key value # set the value of key to value only if all key does not exist

Getset key new-value # sets the value of the string key to the new value and returns the old value

Getset aaa 444

Get key # get key value

Get name

Mset key1 value1 key2 value2. # set multiple key values

Mset gender M age 18 addr SH

Mget key1 key2 key3... # get multiple key values

Mget gender age addr

Append key value # add value to append the content to the end of the string

Append name 123-> "daiby123"

Strlen key # returns the length of the value stored by the string key key. Redis records the length of each string value, time complexity O (1)

Strlen aaa

Setrange key index value # starts with the index index, overrides the string value stored by the key with value, and accepts only positive indexes

Setrange aaa 1222-- > 4222

Getrange key start stop # range value, returns the value between the start and end indexes. The closed interval. The index can be positive or negative.

Getrange aaa 0 2

Getrange aaa 0-2

# commands for numeric values can be executed on a string key as long as the value stored in the string key can be interpreted as a 64-bit integer or an IEEE-754 standard 64-bit floating-point number

# append,strlen,setrange,getrange can be performed even if the string key stores a numeric value

Incrby key increment # add the value stored by key to the incremental increment

Incrby aaa 100

Decrby key decrement # subtracts the value stored in key by subtracting decrement

Decrby aaa 1000

Incr key # plus one, equivalent to incrby key 1

Incr ccc

Decr key # minus one, equivalent to decrby key 1

Decr ccc

Incrbyfloat key increment # floating point number self-increasing and self-decreasing, without decrbyfloat, the corresponding effect can be achieved by giving a negative value

Incrbyfloat ccc 1.11

Incrbyfloat ccc-23.45

Commands such as # set,get,setnx,append can also be used to set binary data

# unlike the index when storing files, the index of storing binary numbers is decreasing from left to right

> import redis

> r = redis.StrictRedis ()

> r.set ('bites', 0b10010100)

>

> r.append ('bites',0b111) # decimal number 7

>

Setbit key index value # sets the value of binary bits and sets the value of secondary bits on a given index to value

Setbit bites 2 1

Getbit key index # returns the value of the binary bits on a given index

Getbit bites 6

Bitcount key start end # calculates and returns the number of binary bits set to 1 in the value stored in the string

Bitcount bites 0-1

# strlen,setrange,getrange is not applicable to Chinese

# hash is used to store objects. The structure of objects is attributes and values, and the basic type of values is string.

# Hash keys and values can be text, integer, floating point, or binary data

# try to use hash keys to store key-value pairs instead of string keys to avoid naming conflicts and save memory

Hset key field value # set a single property

Hset py1 name daiby

Hsetnx key field value # if field does not exist in the hash key key, the command succeeds

Hsetnx message addr sh

Hmset key field1 value1 field2 value2. # set multiple properties

Hmset py3 name daiby age 18 addr SH

Hexists key field # check whether a given field exists

Hexists message addr

Hkeys key # gets all the attributes of the specified key

Hkeys py3

Hvals key # gets the values of all properties of the specified key

Hvals py3

Hget key field # gets the value of an attribute of the specified key

Hget py1 name

Hgetall key # returns all field value pairs contained in the hash key key

Hgetall message

Hmget key field1 field2... # gets the values of multiple attributes of the specified key

Hmget py3 name age addr

Hdel key field1 field2. # Delete the attribute, and the corresponding value of the attribute will be deleted together. If you want to delete the hash key, delete all the attributes.

Hdel name age addr

Hlen key # returns the number of field value pairs contained in the hash key key

Hlen message

Hincrby key field increment # adds or subtracts the integer increment from the value of field in the hash key key

Hincrby message id-10

Hincrbyfloat key filed increment # is the value of field in the hash key key, plus or minus the floating point increment

Hincrbyfloat message id + 1.1

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