redis的数据类型-List

list既可以作为栈，又可以作为队列（双向链表）

lpush

从list的头部压入一个元素

127.0.0.1:6379> lpush  list1  hello
(integer) 1
127.0.0.1:6379> lpush list1 world
(integer) 2
127.0.0.1:6379> lrange list1 0 -1
1) "world"
2) "hello"

rpush

从list的尾部压入一个元素

127.0.0.1:6379> rpush list2 hello
(integer) 1
127.0.0.1:6379> rpush list2 world
(integer) 2
127.0.0.1:6379> lrange list2 0 -1
1) "hello"
2) "world"

linsert

在key对应list的特定位置前或后添加字符串

注意： 从尾向头的方向为向前

127.0.0.1:6379> lpush list3 one
(integer) 1
127.0.0.1:6379> lpush list3 two
(integer) 2
127.0.0.1:6379> lrange list3
(error) ERR wrong number of arguments for 'lrange' command
127.0.0.1:6379> lrange list3 0 -1
1) "two"
2) "one"
127.0.0.1:6379> linsert list3 before one three
(integer) 3
127.0.0.1:6379> lrange list3 0 -1
1) "two"
2) "three"
3) "one"
127.0.0.1:6379>

lset

设置list中指定下标的元素值

127.0.0.1:6379> lpush list4 one
(integer) 1
127.0.0.1:6379> lpush list4 two
(integer) 2
127.0.0.1:6379> lpush list4 three
(integer) 3
127.0.0.1:6379> lrange list4 0 -1
1) "three"
2) "two"
3) "one"
127.0.0.1:6379> lset list4 1 four
OK
127.0.0.1:6379> lrange list4 0 -1
1) "three"
2) "four"
3) "one"

lrem

从key对应list中删除n个和value相同的元素（n<0从尾删除，n=0全部删除）

127.0.0.1:6379> lpush list4 one
(integer) 4
127.0.0.1:6379> lpush list4 one
(integer) 5
127.0.0.1:6379> lpush list4 one
(integer) 6
127.0.0.1:6379> lrange list4 0  -1
1) "one"
2) "one"
3) "one"
4) "three"
5) "four"
6) "one"
127.0.0.1:6379> lrem list4 3 one
(integer) 3
127.0.0.1:6379> lrange list4 0  -1
1) "three"
2) "four"
3) "one"

ltrim

保留指定key的范围内的数据

127.0.0.1:6379> rpush list5 one
(integer) 1
127.0.0.1:6379> rpush list5 two
(integer) 2
127.0.0.1:6379> rpush list5 three
(integer) 3
127.0.0.1:6379> rpush list5 four
(integer) 4
127.0.0.1:6379> ltrim list5 1  2
OK
127.0.0.1:6379> lrange list5 0 -1
1) "two"
2) "three"

lpop（rpop从尾）

从list的头部删除元素，并返回删除元素

127.0.0.1:6379> rpush list6 one
(integer) 1
127.0.0.1:6379> rpush list6 two
(integer) 2
127.0.0.1:6379> rpush list6 three
(integer) 3
127.0.0.1:6379> lrange list6 0 -1
1) "one"
2) "two"
3) "three"
127.0.0.1:6379> lpop list6
"one"
127.0.0.1:6379> lrange list6 0 -1
1) "two"
2) "three"
127.0.0.1:6379> rpop list6
"three"
127.0.0.1:6379> lrange list6 0 -1
1) "two"

rpoplpush

从第一个list的尾部移除元素并添加到第二个list的头部（此命令操作两个list）

127.0.0.1:6379> lrange  list3 0 -1
1) "two"
2) "three"
3) "one"
127.0.0.1:6379> lrange list4 0 -1
1) "three"
2) "four"
3) "one"
127.0.0.1:6379> rpoplpush list3 list4
"one"
127.0.0.1:6379> lrange  list3 0 -1
1) "two"
2) "three"
127.0.0.1:6379> lrange list4 0 -1
1) "one"
2) "three"
3) "four"
4) "one"

lindex

取list中index位置的元素

127.0.0.1:6379> lrange list4 0 -1
1) "one"
2) "three"
3) "four"
4) "one"
127.0.0.1:6379> lindex list4 0
"one"
127.0.0.1:6379> lindex list4 1
"three"

llen

返回list长度

127.0.0.1:6379> lrange list4 0 -1
1) "one"
2) "three"
3) "four"
4) "one"
127.0.0.1:6379> lindex list4 0
"one"
127.0.0.1:6379> lindex list4 1
"three"
127.0.0.1:6379> llen list4
(integer) 4