Redis数据结构介绍

Redis数据结构

Redis是一个key-value的数据库,key一般是String类型,不过value的类型多种多样:

1. 字符串（String）：最常见的值类型，可以存储任意长度的字符串。

2. 哈希（Hash）：一个键值对的集合，类似于关联数组或字典。每个哈希可以存储多个字段和对应的值。

3. 列表（List）：一个有序的字符串元素集合，可以在列表的两端进行插入、删除和访问操作。

4. 集合（Set）：一个无序的字符串元素集合，不允许重复元素。可以进行集合操作，如交集、并集、差集等。

5. 有序集合（Sorted Set）：类似于集合，但每个元素都关联着一个分数，用于排序和按范围查询。

6. 地理位置（Geospatial）：用于存储地理位置信息的数据类型，可以进行附近位置查询和距离计算。

除了上述数据类型，Redis还提供了一些特殊的数据结构和功能，如位图（Bitmap）、HyperLogLog、Pub/Sub（发布订阅）等。

通过使用不同的数据类型，Redis可以适应各种场景和需求，提供高效的数据存储和访问。您可以根据具体的应用需求选择适合的数据类型来存储和操作数据。

在redis-cli中要获取关于数据类型的帮助信息，可以在redis-cli中输入以下命令来获取相关帮助：（help @数据类型）

127.0.0.1:6380> help @string

  APPEND key value
  summary: Appends a string to the value of a key. Creates the key if it doesn't exist.
  since: 2.0.0

  DECR key
  summary: Decrements the integer value of a key by one. Uses 0 as initial value if the key doesn't exist.
  since: 1.0.0

  DECRBY key decrement
  summary: Decrements a number from the integer value of a key. Uses 0 as initial value if the key doesn't exist.
  since: 1.0.0

  GET key
  summary: Returns the string value of a key.
  since: 1.0.0

  GETDEL key
  summary: Returns the string value of a key after deleting the key.
  since: 6.2.0

  GETEX key [EX seconds|PX milliseconds|EXAT unix-time-seconds|PXAT unix-time-milliseconds|PERSIST]
  summary: Returns the string value of a key after setting its expiration time.
  since: 6.2.0

  GETRANGE key start end
  summary: Returns a substring of the string stored at a key.
  since: 2.4.0

  GETSET key value
  summary: Returns the previous string value of a key after setting it to a new value.
  since: 1.0.0

  INCR key
  summary: Increments the integer value of a key by one. Uses 0 as initial value if the key doesn't exist.
  since: 1.0.0

  INCRBY key increment
  summary: Increments the integer value of a key by a number. Uses 0 as initial value if the key doesn't exist.
  since: 1.0.0

  INCRBYFLOAT key increment
  summary: Increment the floating point value of a key by a number. Uses 0 as initial value if the key doesn't exist.
  since: 2.6.0

  LCS key1 key2 [LEN] [IDX] [MINMATCHLEN min-match-len] [WITHMATCHLEN]
  summary: Finds the longest common substring.
  since: 7.0.0

  MGET key [key ...]
  summary: Atomically returns the string values of one or more keys.
  since: 1.0.0

  MSET key value [key value ...]
  summary: Atomically creates or modifies the string values of one or more keys.
  since: 1.0.1

  MSETNX key value [key value ...]
  summary: Atomically modifies the string values of one or more keys only when all keys don't exist.
  since: 1.0.1

  PSETEX key milliseconds value
  summary: Sets both string value and expiration time in milliseconds of a key. The key is created if it doesn't exist.
  since: 2.6.0

  SET key value [NX|XX] [GET] [EX seconds|PX milliseconds|EXAT unix-time-seconds|PXAT unix-time-milliseconds|KEEPTTL]
  summary: Sets the string value of a key, ignoring its type. The key is created if it doesn't exist.
  since: 1.0.0

  SETEX key seconds value
  summary: Sets the string value and expiration time of a key. Creates the key if it doesn't exist.
  since: 2.0.0

  SETNX key value
  summary: Set the string value of a key only when the key doesn't exist.
  since: 1.0.0

  SETRANGE key offset value
  summary: Overwrites a part of a string value with another by an offset. Creates the key if it doesn't exist.
  since: 2.2.0

  STRLEN key
  summary: Returns the length of a string value.
  since: 2.2.0

  SUBSTR key start end
  summary: Returns a substring from a string value.
  since: 1.0.0

127.0.0.1:6380>