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redis list类型命令的实现

作者:不想睡觉的橘子君

本文主要介绍了redis list类型命令的实现,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧

redis的list类型,可以存储双向链表作为value,key保留有head和tail指针可以指向双向链表的头和尾,因此可以直接从头或尾对list进行操作。
全部命令如下:

127.0.0.1:6379> help @list
  BLMOVE source destination LEFT|RIGHT LEFT|RIGHT timeout
  summary: Pop an element from a list, push it to another list and return it; or block until one is available
  since: 6.2.0
  BLMPOP timeout numkeys key [key ...] LEFT|RIGHT [COUNT count]
  summary: Pop elements from a list, or block until one is available
  since: 7.0.0
  BLPOP key [key ...] timeout
  summary: Remove and get the first element in a list, or block until one is available
  since: 2.0.0
  BRPOP key [key ...] timeout
  summary: Remove and get the last element in a list, or block until one is available
  since: 2.0.0
  BRPOPLPUSH source destination timeout
  summary: Pop an element from a list, push it to another list and return it; or block until one is available
  since: 2.2.0
  LINDEX key index
  summary: Get an element from a list by its index
  since: 1.0.0
  LINSERT key BEFORE|AFTER pivot element
  summary: Insert an element before or after another element in a list
  since: 2.2.0
  LLEN key
  summary: Get the length of a list
  since: 1.0.0
  LMOVE source destination LEFT|RIGHT LEFT|RIGHT
  summary: Pop an element from a list, push it to another list and return it
  since: 6.2.0
  LMPOP numkeys key [key ...] LEFT|RIGHT [COUNT count]
  summary: Pop elements from a list
  since: 7.0.0
  LPOP key [count]
  summary: Remove and get the first elements in a list
  since: 1.0.0
  LPOS key element [RANK rank] [COUNT num-matches] [MAXLEN len]
  summary: Return the index of matching elements on a list
  since: 6.0.6
  LPUSH key element [element ...]
  summary: Prepend one or multiple elements to a list
  since: 1.0.0
  LPUSHX key element [element ...]
  summary: Prepend an element to a list, only if the list exists
  since: 2.2.0
  LRANGE key start stop
  summary: Get a range of elements from a list
  since: 1.0.0
  LREM key count element
  summary: Remove elements from a list
  since: 1.0.0
  LSET key index element
  summary: Set the value of an element in a list by its index
  since: 1.0.0
  LTRIM key start stop
  summary: Trim a list to the specified range
  since: 1.0.0
  RPOP key [count]
  summary: Remove and get the last elements in a list
  since: 1.0.0
  RPOPLPUSH source destination
  summary: Remove the last element in a list, prepend it to another list and return it
  since: 1.2.0
  RPUSH key element [element ...]
  summary: Append one or multiple elements to a list
  since: 1.0.0
  RPUSHX key element [element ...]
  summary: Append an element to a list, only if the list exists
  since: 2.2.0

下面示例如下:

这样2个同向的命令组合起来,可以实现一个队列。

反向的命令组合起来,可以实现一个栈。

127.0.0.1:6379> lpush k1 a b c d e
(integer) 5
127.0.0.1:6379> lpop k1
"e"
127.0.0.1:6379> lpop k1
"d"

lrange :lrange key start end,展示key对应的从下标start到end的所有数据

127.0.0.1:6379> lrange k1 0 -1
1) "c"
2) "b"
3) "a"

lindex:lindex key index ,返回key对应的List指定index位置的值

127.0.0.1:6379> lrange k1 0 -1
1) "f"
2) "e"
3) "d"
4) "c"
5) "b"
6) "a"
127.0.0.1:6379> lindex k1 1
"e"

lset:lset key index value,在key对应的list中的指定下标处替换为value

127.0.0.1:6379> lset k1 3 x
OK
127.0.0.1:6379> lrange k1 0 -1
1) "f"
2) "e"
3) "d"
4) "x"
5) "b"
6) "a"

lrem:lrem key num target,删除key对应的list中的target元素,如果num大于0,从head开始删num个。如果num小于0,从tail开始删abs(num)个

127.0.0.1:6379> lrange k3 0 -1
 1) "d"
 2) "6"
 3) "a"
 4) "5"
 5) "c"
 6) "4"
 7) "a"
 8) "3"
 9) "b"
10) "2"
11) "a"
12) "1"
127.0.0.1:6379> lrem k3 2 a
(integer) 2
127.0.0.1:6379> lrange k3 0 -1
 1) "d"
 2) "6"
 3) "5"
 4) "c"
 5) "4"
 6) "3"
 7) "b"
 8) "2"
 9) "a"
10) "1"

linsert:linsert key before/after element value,在key对应的list中,在元素element(不是下标)之前或者之后,添加value

127.0.0.1:6379> lrange k3 0 -1
 1) "d"
 2) "6"
 3) "5"
 4) "c"
 5) "4"
 6) "3"
 7) "b"
 8) "2"
 9) "a"
10) "1"
127.0.0.1:6379> linsert k3 after 6 a
(integer) 11
127.0.0.1:6379> lrange k3 0 -1
 1) "d"
 2) "6"
 3) "a"
 4) "5"
 5) "c"
 6) "4"
 7) "3"
 8) "b"
 9) "2"
10) "a"
11) "1"

llen:llen key,返回长度
redis的List类型有很多关于下标的操作,也可以将其抽象为一个数组来使用。

127.0.0.1:6379> llen k3
(integer) 10

blpop:blpop key time,弹出指定key对应的list中的一个元素,如果list没有元素或者不存在key对应的这个list,则阻塞等待time指定的时间,0表示一直等待,单位是s。

127.0.0.1:6379> blpop k1 0

阻塞期间如果list有了元素,则会中断阻塞并弹出

127.0.0.1:6379> blpop k1 0
1) "k1"
2) "a"
(35.77s)

ltrim:ltrim key start end,删除key对应的list start和end之外的两端的元素

127.0.0.1:6379> lrange k4 0 -1
1) "f"
2) "e"
3) "d"
4) "c"
5) "b"
6) "a"
127.0.0.1:6379> ltrim k4 1 -2
OK
127.0.0.1:6379> lrange k4 0 -1
1) "e"
2) "d"
3) "c"
4) "b"

到此这篇关于redis list类型命令的实现的文章就介绍到这了,更多相关redis list类型内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

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