Redis list常用命令

什麼是redis的list數據結構？

List類型是一個雙端鏈表的結構，容量是2的32次方減1個元素，即40多億個；
其主要功能有push、pop、獲取元素等；一般應用在棧、隊列、消息隊列等場景。

Redis list命令實戰

[LR]PUSH key value1 [value2 …]

以頭插或尾插方式插入指定key隊列中一個或多個元素

LRANGE key start stop

獲取列表指定範圍內的元素

127.0.0.1:6379> lpush products 1 2 3
(integer) 3
127.0.0.1:6379> lpush products 4 5 6
(integer) 6
127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "4"
4) "3"
5) "2"
6) "1"

LINSERT key BEFORE|AFTER pivot value

在列表的元素前或者後插入元素

127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "4"
4) "3"
5) "2"
6) "1"
127.0.0.1:6379> linsert products before 4 a
(integer) 7
127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "a"
4) "4"
5) "3"
6) "2"
7) "1"
127.0.0.1:6379> linsert products after 4 b
(integer) 8
127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "a"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"

LLEN key

獲取列表長度

127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "a"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"
127.0.0.1:6379> llen products
(integer) 8

LINDEX key index

通過索引獲取列表中的元素

127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "a"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"
127.0.0.1:6379> lindex products 2
"a"

LSET key index value

通過索引設置列表元素的值

127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "a"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"
127.0.0.1:6379> lset products 2 A
OK
127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "A"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"

LTRIM key start end

截取隊列指定區間的元素,其餘元素都刪除

127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "A"
4) "4"
5) "b"
6) "3"
7) "2"
8) "1"
127.0.0.1:6379> ltrim products 0 3
OK
127.0.0.1:6379> lrange products 0 -1
1) "6"
2) "5"
3) "A"
4) "4"

LREM key count value

移除列表元素

127.0.0.1:6379> lpush test a 1 a 2 a 3 a 4  5 6
(integer) 10
127.0.0.1:6379> lrange  test 0 -1
 1) "6"
 2) "5"
 3) "4"
 4) "a"
 5) "3"
 6) "a"
 7) "2"
 8) "a"
 9) "1"
10) "a"
127.0.0.1:6379> lrem test 4 a
(integer) 4
127.0.0.1:6379> lrange  test 0 -1
1) "6"
2) "5"
3) "4"
4) "3"
5) "2"
6) "1"

[LR]POP key

從隊列的頭或未彈出節點元素(返回該元素並從隊列中刪除)

127.0.0.1:6379> lrange  test 0 -1
1) "6"
2) "5"
3) "4"
4) "3"
5) "2"
6) "1"
127.0.0.1:6379> lpop test
"6"
127.0.0.1:6379> lrange  test 0 -1
1) "5"
2) "4"
3) "3"
4) "2"
5) "1"
127.0.0.1:6379> lpop test
"5"
127.0.0.1:6379> lrange  test 0 -1
1) "4"
2) "3"
3) "2"
4) "1"

RPOPLPUSH source destination

移除列表的最後一個元素，並將該元素添加到另一個列表並返回

127.0.0.1:6379> lrange src 0 -1
1) "3"
2) "2"
3) "1"
127.0.0.1:6379> lrange dst 0 -1
1) "c"
2) "b"
3) "a"
127.0.0.1:6379> rpoplpush src dst
"1"
127.0.0.1:6379> lrange src 0 -1
1) "3"
2) "2"
127.0.0.1:6379> lrange dst 0 -1
1) "1"
2) "c"
3) "b"
4) "a"

B[LR]POP key1 [key2 …] timeout

移出並獲取列表的第一個或最後一個元素， 如果列表沒有元素會阻塞列表直到等待超時或發現可彈出元素爲止。

127.0.0.1:6379> lpush list1 1 2
(integer) 2
127.0.0.1:6379> lpush list2 a b
(integer) 2
127.0.0.1:6379> lrange list1 0 -1
1) "2"
2) "1"
127.0.0.1:6379> lrange list2 0 -1
1) "b"
2) "a"
127.0.0.1:6379> blpop list1 list2 10
1) "list1"   #彈出元素所屬的列表
2) "2"       #彈出元素所屬的值
127.0.0.1:6379> blpop list1 list2 10
1) "list1"
2) "1"
127.0.0.1:6379> blpop list1 list2 10
1) "list2"
2) "b"
127.0.0.1:6379> blpop list1 list2 10
1) "list2"
2) "a"
127.0.0.1:6379> blpop list1 list2 10
(nil)
(10.08s)  # 列表爲空的時候，就等待超時