Redis存储五种类型数据（redis能储存几种数据）

Redis: Storing Five Different Types of Data

Redis is a popular open-source data structure server that can be used as a database, cache, and message broker. It is known for its easy-to-use interface and high-speed performance. Redis supports various data types, making it a versatile solution for different use cases. In this article, we will explore the five different data types supported by Redis.

1. Strings

Strings are one of the basic data types in Redis. They can store text, binary data, and integers of varying sizes. Redis provides various commands to manipulate strings, such as set, get, append, and increment. Let’s see some examples:

> SET key "hello"
OK
> GET key
"hello"
> APPEND key " world"
OK
> GET key
"hello world"
> INCR counter
1
> INCRBY counter 5
6

As you can see, we can set a string value to a key, retrieve it, append to it, and even increment an integer value.

2. Lists

Lists are another type of data structure supported by Redis. They can store strings, integers, or other Redis data types in a sequence. Redis provides commands to push, pop, index, and range elements in a list. Let’s look at some examples:

> RPUSH mylist "item1" "item2" "item3"
3
> LRANGE mylist 0 -1
1) "item1"
2) "item2"
3) "item3"
> LPOP mylist
"item1"
> RPUSH mylist 100
4

We can push multiple items to a list, retrieve all items, pop the first item, and push a new item.

3. Sets

Sets are another type of data structure in Redis. They store unordered unique values of strings, integers, or other Redis data types. Redis provides operations to add, remove, check membership, and perform set operations (union, intersection, difference) on sets. Here are some examples:

> SADD myset "item1" "item2" "item3"
3
> SMEMBERS myset
1) "item1"
2) "item2"
3) "item3"
> SISMEMBER myset "item3"
1
> SREM myset "item2"
1
> SADD myset2 "item2" "item4"
2
> SUNION myset myset2
1) "item1"
2) "item3"
3) "item2"
4) "item4"

We can add multiple items to a set, get all items, check if an item is a member, remove an item, and perform set operations on sets.

4. Hashes

Hashes are a key-value data structure in Redis. They are similar to Python dictionaries or JavaScript objects. Hashes can store strings, integers, or other Redis data types as values. Redis provides commands to set, get, delete, and iterate over fields in a hash. Here are some examples:

> HMSET myhash field1 "value1" field2 2
OK
> HGET myhash field1
"value1"
> HGETALL myhash
1) "field1"
2) "value1"
3) "field2"
4) "2"
> HDEL myhash field2
1

We can set multiple fields and values in a hash, get the value of a field, get all fields and values, and delete a field.

5. Sorted Sets

Sorted sets are another data structure in Redis that stores elements scored by a floating-point value called a score. Sorted sets can be used to implement leaderboards, rankings, and other scenarios that require sorting. Redis provides commands to add, remove, and retrieve elements by rank or score. Here are some examples:

> ZADD myzset 1 "item1"
1
> ZADD myzset 2 "item2"
1
> ZRANGE myzset 0 -1
1) "item1"
2) "item2"
> ZREM myzset "item1"
1
> ZRANK myzset "item2"
0
> ZADD myzset 3 "item3"
1
> ZRANGEBYSCORE myzset 1 3
1) "item2"
2) "item3"

We can add elements to a sorted set with a score, retrieve elements by rank or score, and remove elements.

Conclusion

Redis supports five different types of data: strings, lists, sets, hashes, and sorted sets. Each data type has its own set of commands for manipulation. Redis’s flexibility makes it a great choice for a wide variety of use cases, from caching to real-time data processing.