(Free red envelope cover) [Redis series] Redis learning four, set collection, hash hash, zset ordered collection preliminary understanding

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set collection

The data in the set collection cannot be re-read

• SADD key member [member ...]

Add elements to the set collection

• SMEMBERS key

View all elements in a collection

• SISMEMBER key member

Check if a certain data is in the collection

• SCARD key

View the number of set data, that is, the length of the set

• SREM key member [member ...]

removes the specified element from the collection

127.0.0.1:6379> sadd myset "hello"
(integer) 1
127.0.0.1:6379> sadd myset "wolrd" "xiaomotong"
(integer) 2
127.0.0.1:6379> SMEMBERS myset
1) "wolrd"
2) "xiaomotong"
3) "hello"
127.0.0.1:6379> SISMEMBER myset hello
(integer) 1
127.0.0.1:6379> SCARD myset
(integer) 3
127.0.0.1:6379> SREM myset wolrd
(integer) 1
127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "hello"

• SRANDMEMBER key [count]

Randomly get the data in the collection, you can specify the number

127.0.0.1:6379> sadd myset "v1" "v2" "v3" "v4"
(integer) 4
127.0.0.1:6379> SMEMBERS myset
1) "v4"
2) "xiaomotong"
3) "v1"
4) "v2"
5) "hello"
6) "v3"
127.0.0.1:6379> SRANDMEMBER myset
"v2"
127.0.0.1:6379> SRANDMEMBER myset
"xiaomotong"
127.0.0.1:6379> SRANDMEMBER myset 2
1) "v4"
2) "v1"
127.0.0.1:6379>
127.0.0.1:6379> SRANDMEMBER myset 2
1) "xiaomotong"
2) "v1"

• SPOP key [count]

Randomly remove any element from a collection

127.0.0.1:6379> SMEMBERS myset
1) "v4"
2) "xiaomotong"
3) "v1"
4) "v2"
5) "hello"
6) "v3"
127.0.0.1:6379> SPOP myset
"v2"
127.0.0.1:6379> SMEMBERS myset
1) "v4"
2) "xiaomotong"
3) "v1"
4) "hello"
5) "v3"
127.0.0.1:6379> SPOP myset
"v4"
127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "v1"
3) "hello"
4) "v3"

• SMOVE source destination member

Take an element from the specified set and put it into another set

127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "v1"
3) "hello"
4) "v3"
127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "v1"
3) "hello"
4) "v3"
127.0.0.1:6379> SMOVE myset newset v1
(integer) 1
127.0.0.1:6379> SMEMBERS newset
1) "v1"
127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "hello"
3) "v3"

• SUNION key [key ...]

Take the union, take the union of two sets

• SINTER key [key ...]

Take the intersection, take the intersection of two sets

127.0.0.1:6379> SMEMBERS myset
1) "xiaomotong"
2) "hello"
3) "v3"
127.0.0.1:6379> sadd newset v3
(integer) 1
127.0.0.1:6379> sadd newset v6 v9
(integer) 2
127.0.0.1:6379> SUNION myset newset
1) "v3"
2) "hello"
3) "xiaomotong"
4) "v1"
5) "v6"
6) "v9"
127.0.0.1:6379> SINTER myset newset
1) "v3"
127.0.0.1:6379>

Set application scenarios can include common concerns of multiple users, friend recommendations, common fans, functional hobbies, etc.

hash hash

Map collection, key-map, at this time key-value is a collection, which is essentially no different from string type, or a simple key-value form

• HSET key field value [field value ...] / HMSET key field value [field value ...]

Add 1 or more key-values to the hash key

• HGET key field

Get the value corresponding to a key in the hash

• HMGET key field [field ...]

Get the value corresponding to multiple keys in the hash

• HGETALL key

Get all key-value pairs in the hash

127.0.0.1:6379> hset myhash name xiaomotong age 12 hobby play
(integer) 3
127.0.0.1:6379> hget myhash name
"xiaomotong"
127.0.0.1:6379> hmget myhash name age
1) "xiaomotong"
2) "12"
127.0.0.1:6379> hgetall myhash
1) "name"
2) "xiaomotong"
3) "age"
4) "12"
5) "hobby"
6) "play"

• HDEL key field [field ...]

Delete the key in the hash, one or more

127.0.0.1:6379> HSET myhash k1 v1 k2 v2 k3 v3
(integer) 3
127.0.0.1:6379> hgetall
(error) ERR wrong number of arguments for 'hgetall' command
127.0.0.1:6379> hgetall myhash
 1) "age"
 2) "12"
 3) "hobby"
 4) "play"
 5) "k1"
 6) "v1"
 7) "k2"
 8) "v2"
 9) "k3"
10) "v3"
127.0.0.1:6379> HDEL myhash k1 k2
(integer) 2
127.0.0.1:6379> HDEL myhash name
(integer) 1
127.0.0.1:6379> hgetall myhash
1) "age"
2) "12"
3) "hobby"
4) "play"
5) "k3"
6) "v3"

• HLEN key

Get the length of the hash, which is the logarithm of the key-value

127.0.0.1:6379> HLEN myhash
(integer) 3

• HINCRBY key field increment

Add a value to a key in the collection, plus if the value is positive, minus if the value is negative

• HSETNX key field value

Add a key-value pair to the hash, add it if it does not exist, and fail to add it if it exists

127.0.0.1:6379> hset myhash age 12
(integer) 1
127.0.0.1:6379> HINCRBY myhash age 2
(integer) 14
127.0.0.1:6379> HINCRBY myhash age -1
(integer) 13
127.0.0.1:6379> HSETNX myhash name xiaozhu
(integer) 1
127.0.0.1:6379> HSETNX myhash name xiaopangzi
(integer) 0
127.0.0.1:6379> hgetall myhash
1) "age"
2) "13"
3) "name"
4) "xiaopangzi"

The application scenarios of hash are, where data is frequently changed, especially some user information, frequently changed information

Hash is more suitable for object storage, string is more suitable for string storage

zset sorted set

zset is also a set, just adding a value to the set

• ZADD key [NX|XX] [GT|LT] [CH] [INCR] score member [score member ...]

Add scores and values to an ordered set, you can add multiple

• ZRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count]

Sort by fractional order, -inf is negative infinity, +inf is positive infinity

• ZRANGE key min max [BYSCORE|BYLEX] [REV] [LIMIT offset count] [WITHSCORES]

View all values in a sorted set

127.0.0.1:6379> ZADD myage 10 xiaoming 8 xiaohong 19 xiaozhu
(integer) 3
127.0.0.1:6379> ZRANGEBYSCORE myage 0 -1
(empty array)
127.0.0.1:6379> ZRANGEBYSCORE myage -inf +inf
1) "xiaohong"
2) "xiaoming"
3) "xiaozhu"
127.0.0.1:6379> ZRANGEBYSCORE myage -inf +inf withscores
1) "xiaohong"
2) "8"
3) "xiaoming"
4) "10"
5) "xiaozhu"
6) "19"
127.0.0.1:6379> ZRANGEBYSCORE myage -inf 10
1) "xiaohong"
2) "xiaoming"
127.0.0.1:6379> ZRANGE myage 0 -1
1) "xiaohong"
2) "xiaoming"
3) "xiaozhu"

• ZREM key member [member ...]

delete data from sorted set

127.0.0.1:6379> ZREM myage xiaoming
(integer) 1
127.0.0.1:6379> ZRANGEBYSCORE myage -inf +inf withscores
1) "xiaohong"
2) "8"
3) "xiaozhu"
4) "19"

• ZREVRANGE key start stop [WITHSCORES]

Sort a sorted set from largest to smallest

127.0.0.1:6379> ZADD myage 7 xiaohe 17 xiaoliu 14 huhu
(integer) 3
127.0.0.1:6379> ZRANGE myage 0 -1
1) "xiaohe"
2) "xiaohong"
3) "huhu"
4) "xiaoliu"
5) "xiaozhu"
127.0.0.1:6379> ZRANGEBYSCORE myage -1 20
1) "xiaohe"
2) "xiaohong"
3) "huhu"
4) "xiaoliu"
5) "xiaozhu"
127.0.0.1:6379> ZRANGEBYSCORE myage -1 20 withscores
 1) "xiaohe"
 2) "7"
 3) "xiaohong"
 4) "8"
 5) "huhu"
 6) "14"
 7) "xiaoliu"
 8) "17"
 9) "xiaozhu"
10) "19"
127.0.0.1:6379> ZREVRANGE myage 0 -1
1) "xiaozhu"
2) "xiaoliu"
3) "huhu"
4) "xiaohong"
5) "xiaohe"

For the rest of the api, we can go to the redis official website to learn and practice, you can view the official Chinese document of redis, http://www.redis.cn/

The application scenarios of zset are:

set sorting, storing class grade information, salary information, etc., used for sorting and filtering

Data or messages with weights, implementation of leaderboards, etc.

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