I List list
The linked list based implementation element is a string type
The addition and deletion at the beginning and end of the list is fast, the addition and deletion in the middle is slow, and the addition and deletion of elements is normal
Elements can be repeated
Contains up to 2 ^ 32-1 elements
Index of the list
From left to right, starting from 0
From right to left, starting from – 1
1. Press in elements left and right or head and tail
LPUSH key value [value …]
LPUSHX key value
RPUSH key value [value …]
RPUSHX key value
2. Left and right or head and tail pop-up elements
LPOP key RPOP key
3. Pop up elements from the end of one list and press them into the head of another list
RPOPLPUSH source destination
4. Return the specified range element in the list
Lrange key start stop lrange key 0 – 1 indicates that all elements are returned
5. Get the element at the specified location
LINDEX key index
6. Set the value of the specified location element
LSET key index value
7. List length and number of elements
LLEN key
8. Delete the element with value equal to value count times from the list header
LREM key count value
Count > 0: search from the header to the footer, and remove elements equal to value. The number is count
Count < 0: search from the end of the table to the header, remove elements equal to value, and the quantity is the absolute value of count
Count = 0: remove all values equal to value in the table
9. Remove elements outside the specified range
LTRIM key start stop
10.Inserts an element before or after an existing value (pivot) in the list
LINSERT key BEFORE|AFTER pivot value
Key and pivot do not exist. No operation is required
11. Blocking
If the pop-up list does not exist or is empty, it will be blocked
If the timeout is set to 0, it is permanently blocked until there is data to pop up
If multiple clients are blocked on the same list, use the first in first service principle to provide first come first service
Left and right or head and tail blocking pop-up elements
BLPOP key [key …] timeout
BRPOP key [key …] timeout
II HSH hash
1. Features
A map key value pair consisting of a field and an associated value
Field and value are string types in a hash
Contains up to 2 ^ 32-1 key value pairs
2. Set a single field
HSET key field value
HSETNX key field value
Execute when the filed of the key does not exist, and create it directly if the key does not exist
3. Set multiple fields
HMSET key field value [field value …]
4. Return the number of fields
HLEN key
5. Judge whether the field exists
HEXISTS key field
If the key or field does not exist, 0 is returned
6. Return field value
HGET key field
7. Return multiple field values
HMGET key field [field …]
8. Return all key value pairs
HGETALL key
9. Return all field names
HKEYS key
10. Return all values
HVALS key
11. Perform incremental calculation of integers on the value corresponding to the field
HINCRBY key field increment
12. Perform incremental calculation of floating point number on the value corresponding to the field
HINCRBYFLOAT key field increment
13. Delete the specified field
HDEL key field [field …]
14. Purpose of hash
1) Save memory space
2) Every time a key is created, it will store some additional management information for the key (such as the type of the key, the last time the key was accessed, etc.)
3) Therefore, the more keys in the database, the more memory the redis database server will consume in storing additional management information, and the more CPU it will spend on the management database keys. It will perform incremental floating-point calculation on the value corresponding to the field
15. Not suitable for hash
1) Use binary operation commands: redis currently supports setbit, getbit, bitop and other operations on string keys. If you want to use these operations, you can only use string keys, although hash can also save binary data
2) Use expiration key function: redis’s key expiration function can only expire keys, not hash fields. Therefore, if you want to use the expiration function for key value pairs, you can only store key value pairs in the string
III Set set
1. Features
Disordered, de duplicated
Element is a string type
Contains up to 2 ^ 32-1 elements
2. Add one or more elements
SADD key member [member …]
If the element already exists, it is automatically ignored
3. Remove one or more elements
SREM key member [member …]
Element does not exist, ignored automatically
4. Return all elements contained in the collection
SMEMBERS key
If there are too many collection elements, such as millions, which need to be traversed, it may cause server blocking, which should be avoided in the production environment
5. Disorder of sets‘
SADD friends “peter” “jack” “tom” “john” “may” “ben”
SADD anotherfriends “peter” “jack” “tom” “john” “may” “ben”
SMEMBERS friends
SMEMBERS anotherfriends
Note that SMEs may return different results. Therefore, if you need to store ordered and non repetitive data, use an ordered set to store an ordered and repeatable use list
6. Randomly return the specified number in the set
SRANDMEMBER key [count]
If count is positive and less than the set cardinality, the command returns an array of count elements, each of which is different.
If count is greater than or equal to the collection cardinality, the entire collection is returned
If count is negative, the command returns an array. The elements in the array may appear multiple times, and the length of the array is the absolute value of count
If count is 0, null is returned. If count is not specified, a random element is returned
7. Return the number of elements in the collection
The result of the scar key will save the information, and the collection length will be recorded in it, so there is no need to traverse
8. Randomly remove from the collection and return the removed element
SPOP key
9. Difference set
SDIFF key [key …]， Remove the intersection of other sets and itself from the set of the first key
SDIFFSTORE destination key [key …]， Store the difference result in the target key
10. Intersection
SINTER key [key …]， Take the intersection of all sets
SINTERSTORE destination key [key …]， Store the intersection result in the target key
11. Union
SUNION key [key …]， Union of all sets
SUNIONSTORE destination key [key …]， Store the union result in the target key
IV Sortedset ordered set
1. Features
Similar to set set
Orderly and de duplication
Element is a string type
Each element is associated with a floating point score, and the elements in the collection are arranged in the order of the score from small to large.
The score can be the same and can contain up to 2 ^ 32-1 elements
2. Add one or more elements
ZADD key score member [score member …]
If the element already exists, a new score is used
give an example
Zadd fruits 3.2 bananas
Zadd fruits 2.0 watermelon
Zadd fruits 4.0 guava 7.0 pear 6.8 mango
3. Remove one or more elements
ZREM key member [member …]
Element does not exist, ignored automatically
give an example
Zrem fruits guava pear mango
Zrem fruits watermelon
4. Display score
ZSCORE key member
give an example
Zscore fruits mango
Zscore fruits watermelon
The computer can not accurately express every floating-point number. It is an approximate expression
5. Increase or decrease the score
If zincrby key increment member increment is negative, it means decrease
For example, zincrby fruits 1.5 watermelon zincrby fruits – 0.8 banana
6. Return the ranking (index) of elements
ZRANK key member
Example: zrank fruits watermelon
Zrank fruits guava
Zrank fruits mango
7. Return the reverse ranking of elements
ZREVRANK key member
8. Return the element of the specified index interval
ZRANGE key start stop [WITHSCORES]
If the scores are the same, they are arranged according to the lexicographic order. By default, the scores are arranged from small to large. If you need to arrange the scores from large to small, use zrevrange
9. Return the element of the specified score range
ZRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count]
The returned score is between [min, Max] by default. The elements are arranged in ascending order according to the score, and the score is in the same dictionary order
In limit, offset represents how many elements are skipped, and count is how many elements are returned. Similar to MySQL
Use parentheses to change the interval to an open interval, such as (5), (10, 5)
-Inf and + inf represent negative infinity and positive infinity
10. Return the element of the specified score range
ZREVRANGEBYSCORE key min max [WITHSCORES] [LIMIT offset count]
The returned score is between [min, Max] by default, and the elements are arranged in descending order according to the score, which is the same as the descending order of the dictionary
In limit, offset represents how many elements are skipped, and count is how many elements are returned. Similar to MySQL
Use parentheses to change the interval to an open interval, such as (5), (10, 5)
-Inf and + inf represent negative infinity and positive infinity
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11. Remove the elements of the specified ranking range
12. Remove the element of the specified score range
13. Return the number of elements in the set
14. Union
