Redis的List操作

lpush key value
作用: 把值插入到链接头部
127.0.0.1:6379> lpush character a
(integer) 1
127.0.0.1:6379> rpush character b
(integer) 2
127.0.0.1:6379> rpush character c
(integer) 3
127.0.0.1:6379> lpush character 0
(integer) 4

lrange key start  stop
作用: 返回链表中[start ,stop]中的元素
规律: 左数从0开始,右数从-1开始
127.0.0.1:6379> lrange character 1 2
1) "a"
2) "b"
127.0.0.1:6379> lrange character 1 3
1) "a"
2) "b"
3) "c"
127.0.0.1:6379> lrange character 0 3
1) "0"
2) "a"
3) "b"
4) "c"
127.0.0.1:6379> lrange character 0 -1//所有元素
1) "0"
2) "a"
3) "b"
4) "c"

rpop key
作用: 返回并删除链表尾元素
127.0.0.1:6379> lpop character
"0"
127.0.0.1:6379> lrange character 0 -1
1) "a"
2) "b"
3) "c"
127.0.0.1:6379> rpop character
"c"
127.0.0.1:6379> lrange character 0 -1
1) "a"
2) "b"

lrem key count value
作用: 从key链表中删除 value值
注: 删除count的绝对值个value后结束
Count>0 从表头删除
Count<0 从表尾删除
127.0.0.1:6379> lpush answer a b c a b d a
(integer) 7
127.0.0.1:6379> lrange answer 0 -1
1) "a"
2) "d"
3) "b"
4) "a"
5) "c"
6) "b"
7) "a"
127.0.0.1:6379> lrem answer  1 b
(integer) 1
127.0.0.1:6379> lrange answer 0 -1
1) "a"
2) "d"
3) "a"
4) "c"
5) "b"
6) "a"
127.0.0.1:6379> lrem answer -2 a
(integer) 2
127.0.0.1:6379> lrange answer 0 -1
1) "a"
2) "d"
3) "c"
4) "b"

ltrim key start stop
作用: 剪切key对应的链接,切[start,stop]一段,并把该段重新赋给key
127.0.0.1:6379> rpush character a b c d e f
(integer) 6
127.0.0.1:6379> lrange character 0 -1
1) "a"
2) "b"
3) "c"
4) "d"
5) "e"
6) "f"
127.0.0.1:6379> ltrim character 2 5
OK
127.0.0.1:6379> lrange character 0 -1
1) "c"
2) "d"
3) "e"
4) "f"
127.0.0.1:6379> ltrim character 1 -2
OK
127.0.0.1:6379> lrange character 0 -1
1) "d"
2) "e"

llen key
作用:计算链接表的元素个数
lindex key index
作用: 返回index索引上的值,
127.0.0.1:6379> lrange character 0 -1
1) "d"
2) "e"
127.0.0.1:6379> llen character
(integer) 2
127.0.0.1:6379> rpush character a b c
(integer) 5
127.0.0.1:6379> llen character
(integer) 5
127.0.0.1:6379> lindex character 4
"c"
127.0.0.1:6379> lindex character 0
"d"

linsert  key after|before search value
作用: 在key链表中寻找’search’,并在search值之前|之后,.插入value
注: 一旦找到一个search后,命令就结束了,因此不会插入多个value
127.0.0.1:6379> rpush num 1 3 6 8 9
(integer) 5
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "3"
3) "6"
4) "8"
5) "9"
127.0.0.1:6379> linsert num before 3 2
(integer) 6
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "6"
5) "8"
6) "9"
127.0.0.1:6379> linsert num after 9 10
(integer) 7
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "6"
5) "8"
6) "9"
7) "10"

rpoplpush source dest

作用: 把source的尾部拿出,放在dest的头部,

并返回 该单元值

业务逻辑:

1:Rpoplpush task bak

2:接收返回值,并做业务处理

3:如果成功,rpop bak 清除任务. 如不成功,下次从bak表里取任务

127.0.0.1:6379> rpush task a b c d
(integer) 4
127.0.0.1:6379> lrange task 0 -1
1) "a"
2) "b"
3) "c"
4) "d"
127.0.0.1:6379> rpoplpush task job
"d"
127.0.0.1:6379> lrange job 0 -1
1) "d"
127.0.0.1:6379> rpoplpush task job
"c"
127.0.0.1:6379> lrange job 0 -1
1) "c"
2) "d"
127.0.0.1:6379> lrange task 0 -1
1) "a"
2) "b"

brpop ,blpop  key timeout

作用:等待弹出key的尾/头元素,

Timeout为等待超时时间

如果timeout为0,则一直等待

场景: 长轮询Ajax,在线聊天时,能够用到