1. list列表类型的操作
1.1. lpush/rpush key value [value ...] 链表的头部(左侧)或尾部(右侧)插入值
语法:lpush key value [value ...]
作用:把值插入到列表左侧
语法:rpush key value [value ...]
作用:把值插入到列表右侧
返回值:返回列表的长度
例:
127.0.0.1:6379> lpush animal cat
(integer) 1
127.0.0.1:6379> lpush animal dog
(integer) 2
127.0.0.1:6379> rpush animal monkey
(integer) 3
1.2. lpop/rpop key
语法:lpop key
语法:rpop key
作用:返回并删除列表元素
返回值:删除的元素
例:
127.0.0.1:6379> rpush word apple banana cat dog
(integer) 4
127.0.0.1:6379> lrange word 0 -1
1) "apple"
2) "banana"
3) "cat"
4) "dog"
127.0.0.1:6379> lpop word
"apple"
127.0.0.1:6379> lrange word 0 -1
1) "banana"
2) "cat"
3) "dog"
127.0.0.1:6379> rpop word
"dog"
127.0.0.1:6379> lrange word 0 -1
1) "banana"
2) "cat"
1.3. lrange key start stop
语法:lrange key start stop
作用:返回列表中[start,stop]中的元素
注:左侧从0开始;右侧从-1开始
例:查看列表中所有的元素
127.0.0.1:6379> lrange animal 0 -1
1) "dog"
2) "cat"
3) "monkey"
127.0.0.1:6379> lpush num 1 2 3 4
(integer) 4
127.0.0.1:6379> lrange num 0 -1
1) "4"
2) "3"
3) "2"
4) "1"
127.0.0.1:6379> lrange num 2 3
1) "2"
2) "1"
127.0.0.1:6379> lrange num -2 3
1) "2"
2) "1"
127.0.0.1:6379> lrange num -1 -3 #
(empty list or set)
127.0.0.1:6379> lrange num -3 -1
1) "3"
2) "2"
3) "1"
1.4. lrem key count value
语法:lrem key count value
作用:从key列表中删除value值(从左到右)
注:删除count的绝对值个value后结束
Count>0 从左侧删除
Count<0 从右侧删除
例:
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) "b"
3) "c"
4) "a"
5) "b"
6) "d"
7) "a"
127.0.0.1:6379> lrem answer 1 b #删除第1个b
(integer) 1
127.0.0.1:6379> lrange answer 0 -1
1) "a"
2) "c"
3) "a"
4) "b"
5) "d"
6) "a"
127.0.0.1:6379> lrem answer -2 a #删除最后2个a
(integer) 2
127.0.0.1:6379> lrange answer 0 -1
1) "a"
2) "c"
3) "b"
4) "d"
1.5. Itrim key start stop
语法:ltrim key start stop
作用:剪切key对应的列表,切[start,stop]一段,并把该段重新赋给key
例:
127.0.0.1:6379> rpush word apple banana cat dog
(integer) 4
127.0.0.1:6379> lrange word 0 -1
1) "apple"
2) "banana"
3) "cat"
4) "dog"
127.0.0.1:6379> ltrim word 1 3
OK
127.0.0.1:6379> lrange word 0 -1
1) "banana"
2) "cat"
3) "dog"
127.0.0.1:6379> rpush word a b c d e f
(integer) 6
127.0.0.1:6379> ltrim word 1 -2
OK
127.0.0.1:6379> lrange word 0 -1
1) "b"
2) "c"
3) "d"
4) "e"
127.0.0.1:6379> ltrim word -1 2
OK
127.0.0.1:6379> lrange word 0 -1 #
(empty list or set)
1.6. lindex key index
语法:lindex key index
作用:返回Index索引上的值
例:
127.0.0.1:6379> rpush fruit apple banana ogange pear peach
(integer) 5
127.0.0.1:6379> lindex fruit 0
"apple"
127.0.0.1:6379> lindex fruit 1
"banana"
127.0.0.1:6379> lindex fruit -1
"peach"
1.7. llen key
语法:llen key
作用:计算列表的元素个数
例:
127.0.0.1:6379> rpush fruit apple banana ogange pear peach
(integer) 5
127.0.0.1:6379> llen fruit
(integer) 5
1.8. linsert key BEFORE|AFTER pivot value
语法:linsert key BEFORE|AFTER pivot value
作用:在key列表中寻找pivot,并在pivot值之前/之后插入value
插入成功返回列表的长度
如果找不到pivot,插入失败,返回-1
注:一旦找到一个pivot后,命令就结束了,因此不会插入多个value
例:
127.0.0.1:6379> rpush num 1 3 5 7
(integer) 4
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "3"
3) "5"
4) "7"
127.0.0.1:6379> linsert num before 3 2
(integer) 5
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "5"
5) "7"
127.0.0.1:6379> linsert num after 7 8
(integer) 6
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "5"
5) "7"
6) "8"
127.0.0.1:6379> linsert num after 20 21
(integer) -1
127.0.0.1:6379> linsert num after 8 8
(integer) 7
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "5"
5) "7"
6) "8"
7) "8"
127.0.0.1:6379> linsert num after 8 10
(integer) 8
127.0.0.1:6379> lrange num 0 -1
1) "1"
2) "2"
3) "3"
4) "5"
5) "7"
6) "8"
7) "10"
8) "8"
1.9. rpoplpush source destination
语法:rpoplpush source destination
作用:把source的尾部(右侧)拿出来,放在desinationt的头部(左侧),并返回该单元值
场景:task+bak 双列表完成安全队列
业务逻辑:
rpoplpush task bak
接收返回值,并做业务处理
如果成功,rpop bak清除任务,如果不成功,下次从bak表里取任务
注:此命令实现的功能,用rpop、lpush两个命令也能实现,但是此命令是一个原子操作,如果用两个命令来实现不够原子性(如:rpop成功,lpush失败就没有rpoplpush更安全)
127.0.0.1:6379> rpush task a b c d
(integer) 4
127.0.0.1:6379> rpoplpush task job
"d"
127.0.0.1:6379> lrange task 0 -1
1) "a"
2) "b"
3) "c"
127.0.0.1:6379> lrange job 0 -1
1) "d"