redis ltrim命令
LTRIM key start stop
相关命令
- BLPOP
- BRPOP
- BRPOPLPUSH
- LINDEX
- LINSERT
- LLEN
- LPOP
- LPUSH
- LPUSHX
- LRANGE
- LREM
- LSET
- LTRIM
- RPOP
- RPOPLPUSH
- RPUSH
- RPUSHX
加入版本 1.0.0。
时间复杂度: O(N) where N is the number of elements to be removed by the operation。
Trim an existing list so that it will contain only the specified range of elements specified. Both start
and stop
are zero-based indexes, where 0
is the first element of the list (the head), 1
the next element and so on.
For example: LTRIM foobar 0 2
will modify the list stored at foobar
so that only the first three elements of the list will remain.
start
and end
can also be negative numbers indicating offsets from the end of the list, where -1
is the last element of the list, -2
the penultimate element and so on.
Out of range indexes will not produce an error: if start
is larger than the end of the list, or start > end
, the result will be an empty list (which causes key
to be removed). If end
is larger than the end of the list, Redis will treat it like the last element of the list.
A common use of LTRIM is together with LPUSH / RPUSH. For example:
LPUSH mylist someelement
LTRIM mylist 0 99
This pair of commands will push a new element on the list, while making sure that the list will not grow larger than 100 elements. This is very useful when using Redis to store logs for example. It is important to note that when used in this way LTRIM is an O(1) operation because in the average case just one element is removed from the tail of the list.
Return value
Examples
(integer) 1
redis> RPUSH mylist "two"
(integer) 2
redis> RPUSH mylist "three"
(integer) 3
redis> LTRIM mylist 1 -1
OK
redis> LRANGE mylist 0 -1
1) "two"
2) "three"
redis>
最新文章
- 关于conky
- Web自动化测试 Selenium 3/3 https的配置
- 简单的cookie使用
- CoreLocation 下的定位跟踪测速
- CSS2书写顺序
- c/c++重定向输入输出
- MyBatis 原始Dao开发方式
- vue-router实例
- Go学习——new()和 make()的区别详解(转载)
- SQL中内连接和外连接的问题!
- udp重发
- python笔记1-基础概念、python安装使用配置
- SecureCRT乱码解决
- October 12th 2017 Week 41st Thursday
- BZOJ.4516.[SDOI2016]生成魔咒(后缀数组 RMQ)
- FPGA In/Out Delay Timing Constaint
- 使用注册表优化终端、编辑器的中英字体混合显示,如「Consolas + 雅黑」「Monaco + 雅黑」
- 你使用 Web 平台安装程序命令行工具
- schema in oracle
- bootstrap-select.js 下拉框多选后动态赋值