Redis 資料型態List

• • List是有順序(透過index 進行存取)，可重複的資料結構(value可以重覆)，可以透過索引快速取得資料，但放入(push)與取出(pop)時操作速度較慢，也可以從left或right開始操作．

• 可用指令

  • LPUSH
  • LPUSHX
  • RPUSH
  • RPUSHX
  • LPOP
  • RPOP
  • RPOPLPUSH
  • LREM
  • LLEN
  • LINDEX
  • LINSERT
  • LSET
  • LRANGE
  • LTRIM
  • BLPOP
  • BRPOP
  • BRPOPLPUSH
  • LMOVE
  • BLMOVE

• 資料結構

  • 底層都是使用quicklist取代ziplist與linkedlist．

LPUSH

從左邊插入value．

# 從左邊插入value
127.0.0.1:6379> lpush mylist abc
(integer) 1

# 確認底層型態為quicklist
127.0.0.1:6379> object encoding mylist
"quicklist"

127.0.0.1:6379> lpush mylist abc abc abc
(integer) 3

# value可以重覆
127.0.0.1:6379> lrange mylist 0 3
1) "abc"
2) "abc"
3) "abc"

LPUSHX

當list存在時，從左邊插入value．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

127.0.0.1:6379> lpush mylist abc
(integer) 1

# 從左邊插入值到已存在的list
127.0.0.1:6379> lpushx mylist def
(integer) 2

127.0.0.1:6379> lrange mylist 0 3
1) "def"
2) "abc"

# 無法插入值到不存在的list
127.0.0.1:6379> lpushx mylist2 def
(integer) 0

127.0.0.1:6379> lrange mylist2 0 3
(empty array)

LPOP

從左邊取出value，可以指定一次取出多少個value．

# 取出value
127.0.0.1:6379> lpop mylist
"abc"

# 沒有可以再取出的value
127.0.0.1:6379> lpop mylist
(nil)

# 插入3個value
127.0.0.1:6379> lpush mylist abc def ghi
(integer) 3

127.0.0.1:6379> lrange mylist 0 2
1) "ghi"
2) "def"
3) "abc"

# 一次取出兩個value
127.0.0.1:6379> lpop mylist 2
1) "ghi"
2) "def"

RPUSH

從右邊插入value．

# 從右邊插入value
127.0.0.1:6379> rpush mylist abc
(integer) 1

# 確認底層型態為quicklist
127.0.0.1:6379> object encoding mylist
"quicklist"

RPUSHX

當list存在時，從右邊插入value．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

127.0.0.1:6379> rpush mylist abc
(integer) 1

# 從右邊插入值到已存在的list
127.0.0.1:6379> rpushx mylist def
(integer) 2

127.0.0.1:6379> lrange mylist 0 3
1) "abc"
2) "def"

# 無法插入值到不存在的list
127.0.0.1:6379> rpushx mylist2 def
(integer) 0

RPOP

從右邊取出value，可以指定一次取出多少個value．

# 取出value
127.0.0.1:6379> rpop mylist
"abc"

# 沒有可以再取出的value
127.0.0.1:6379> rpop mylist
(nil)

# 插入3個value
127.0.0.1:6379> rpush mylist abc def ghi
(integer) 3

127.0.0.1:6379> lrange mylist 0 2
1) "abc"
2) "def"
3) "ghi"

# 一次取出兩個value
127.0.0.1:6379> rpop mylist 2
1) "ghi"
2) "def"

LLEN

顯示List中valu的個數．

# 插入3個value
127.0.0.1:6379> lpush mylist abc def ghi
(integer) 3

# 取得List中value的個數
127.0.0.1:6379> llen mylist
(integer) 3

#                      <----
#           -3  -2  -1  Right index
#           abc def ghi
#Left index  0   1   2
#      ---->

LRANGE

取得指定Range的value值．

127.0.0.1:6379> lpush mylist abc def ghi
(integer) 3

# 取出從位置0到位置-1的value
127.0.0.1:6379> lrange mylist 0 -1
1) "ghi"
2) "def"
3) "abc"

# 取出從位置1到位置1的value
127.0.0.1:6379> lrange mylist 1 1
1) "def"

# 取出從位置1到位置2的value
127.0.0.1:6379> lrange mylist 1 2
1) "def"
2) "abc"

# 取出從位置-2到位置1的value
127.0.0.1:6379> lrange mylist -2 1
1) "def"

# 取出從位置-2到位置2的value
127.0.0.1:6379> lrange mylist -2 2
1) "def"
2) "abc"

# 取出從位置-2到位置0的value
127.0.0.1:6379> lrange mylist -2 0
(empty array)

LINDEX

取得指定index的value值．

127.0.0.1:6379> lpush mylist abc def ghi
(integer) 3

# 查詢index 1的value值
127.0.0.1:6379> lindex mylist 1
"def"

# 查詢index 2的value值
127.0.0.1:6379> lindex mylist 2
"abc"

LSET

修改指定index的value值．

127.0.0.1:6379> lindex mylist 0
"ghi"

# 修改
127.0.0.1:6379> lset mylist 0 aaa
OK

127.0.0.1:6379> lindex mylist 0
"aaa"

LTRIM

根據index範圍保留value，除範圍以內的其餘value將被刪除．

127.0.0.1:6379> lrange mylist 0 2
1) "aaa"
2) "def"
3) "abc"

# 刪除指定範圍以外的value
127.0.0.1:6379> ltrim mylist 1 2
OK

127.0.0.1:6379> lrange mylist 0 2
1) "def"
2) "abc"

BRPOP

block 右邊取出，類似long polling機制．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

# 如果list中沒有value，則會等待10秒
127.0.0.1:6379> brpop mylist 10
(nil)
(10.03s)

# 如果10秒內有value插入，則從右邊取出1個value
127.0.0.1:6379> brpop mylist 10
1) "mylist"
2) "aaa"
(1.64s)

BLPOP

block 左邊取出，類似long polling機制．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

# 如果list中沒有value，則會等待10秒
127.0.0.1:6379> blpop mylist 10
(nil)
(10.03s)

# 如果10秒內有value插入，則從左邊取出1個value
127.0.0.1:6379> blpop mylist 10
1) "mylist"
2) "aaa"
(1.32s)

LREM

從左邊開始刪除幾個指定value．

127.0.0.1:6379> lpush mylist abc abc abc
(integer) 3

127.0.0.1:6379> lrange mylist 0 3
1) "abc"
2) "abc"
3) "abc"

# 從左邊開始刪除1個abc的value
127.0.0.1:6379> lrem mylist 1 abc
(integer) 1

127.0.0.1:6379> lrange mylist 0 3
1) "abc"
2) "abc"

# 從左邊開始刪除2個abc的value
127.0.0.1:6379> lrem mylist 2 abc
(integer) 2

127.0.0.1:6379> lrange mylist 0 3
(empty array)

LINSERT

將value插入到指定value之前或之後．

127.0.0.1:6379> lpush mylist abc def
(integer) 2

127.0.0.1:6379> lrange mylist 0 3
1) "def"
2) "abc"

# 在abc此value前插入111的value
127.0.0.1:6379> linsert mylist before abc 111
(integer) 3

127.0.0.1:6379> lrange mylist 0 3
1) "def"
2) "111"
3) "abc"

# 在111此value後插入222的value
127.0.0.1:6379> linsert mylist after 111 222
(integer) 4

127.0.0.1:6379> lrange mylist 0 3
1) "def"
2) "111"
3) "222"
4) "abc"

RPOPLPUSH

指定從某個list取出value並插入到另外一個list．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

127.0.0.1:6379> lpush mylist abc def
(integer) 2

127.0.0.1:6379> lrange mylist2 0 3
(empty array)

#從mylist中取出value abc插入mylist2
127.0.0.1:6379> rpoplpush mylist mylist2
"abc"

127.0.0.1:6379> lrange mylist 0 3
1) "def"

127.0.0.1:6379> lrange mylist2 0 3
1) "abc"

LMOVE

指定從某個list的某方向取出value並插入到另外一個list的指定方向．

127.0.0.1:6379> lrange mylist 0 3
(empty array)

127.0.0.1:6379> lrange mylist2 0 3
(empty array)

127.0.0.1:6379> lpush mylist abc def ghi
(integer) 3

# 從mylist的右邊取出value並插入到mylist2的右邊
127.0.0.1:6379> lmove mylist mylist2 right right
"abc"

127.0.0.1:6379> lrange mylist 0 3
1) "ghi"
2) "def"

127.0.0.1:6379> lrange mylist2 0 3
1) "abc"

# 從mylist的左邊取出value並插入到mylist2的右邊
127.0.0.1:6379> lmove mylist mylist2 left right
"ghi"

127.0.0.1:6379> lrange mylist 0 3
1) "def"

127.0.0.1:6379> lrange mylist2 0 3
1) "abc"
2) "ghi"

BRPOPLPUSH

在6.2版本改用BLMOVE取代．

BLMOVE

跟LMOVE使用方式一樣，但會指定秒數．
指定從某個list的某方向取出value並插入到另外一個list的指定方向．