Hive 高阶应用开发示例(一)
Hive的一些常用的高阶开发
内容
1.开窗函数
2.行转列,列转行,多行转一行,一行转多行
3.分组: 增强型group
4.排序
5.关联
本次的内容: 内容1 和内容2,采用的是示例数据以及对应的实现。数据可以直接放在Hive中执行。可以直观的观察数据,进而对函数以及相应的功能有所熟悉。
对于不同的场景的数据计算,了解SQL的基本语法以及一些高阶用法,在这些基础上组合相应的功能。这些都是一些工程上的应用,多练习的。通过构建数据集来验证的方式,是可以自己来确认一些似是而非的语法。对于Hive底层原理和代码的了解也是途径之一。构建数据集验证与通过原理去分析了解的方法可以相互配合使用。最终的目标之一就是更好的实现业务分析目标。-- over() 子句 有order by, 分区内排序后一个个叠-- windows子句 WINDOW子句(灵活控制窗口的子集)
--
WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '2' AS mem_id , 6 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 7 AS score , '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 9 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, SUM(score) OVER(PARTITION BY mem_id ) AS pv1
, SUM(score) OVER(PARTITION BY mem_id ORDER BY createtime) AS pv1 -- 默认为从起点到当前行
, SUM(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW ) AS pv2 --从起点到当前行,结果同pv1
, SUM(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW ) AS pv3 --当前行+往前3行
, SUM(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING ) AS pv4 --当前行+往前3行+往后1行
, SUM(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv5 -- ---当前行+往后所有行
FROM table_1
;WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 5 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, createtime
, MAX(score) OVER(PARTITION BY mem_id ) AS pv1 -- 分组的
, MAX(score) OVER(PARTITION BY mem_id ORDER BY createtime) AS pv1 -- 默认为从起点到当前行
, MAX(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS pv2 --从起点到当前行,结果同pv1
, MAX(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS pv3 --当前行+往前3行
, MAX(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN 3 PRECEDING AND 1 FOLLOWING) AS pv4 --当前行+往前3行+往后1行
, MAX(score) OVER(PARTITION BY mem_id ORDER BY createtime ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS pv5 ---当前行+往后所有行
FROM table_1
;-- 1.排序开窗函数
-- row_number() :从1开始,按照顺序,生成分组内记录的序列,row_number()的值不会存在重复 1 2 3 4
-- dense_rank() :生成数据项在分组中的排名,排名相等会在名次中不会留下空位 1 2 2 3
-- rank() :生成数据项在分组中的排名,排名相等会在名次中留下空位 1 2 2 4WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 5 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, createtime
, ROW_NUMBER() OVER(PARTITION BY mem_id ORDER BY createtime ) AS ROW_NUMBER_pv1 -- 1 2 3 4
, DENSE_RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS DENSE_RANK_pv2 -- 1 2 2 3
, RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS RANK_pv3 -- 1 2 2 4
, ROW_NUMBER() OVER(PARTITION BY mem_id ORDER BY createtime desc) AS ROW_NUMBER_desc_pv1 -- 1 2 3 4
, DENSE_RANK() OVER(PARTITION BY mem_id ORDER BY createtime desc) AS DENSE_RANK_desc_pv2 -- 1 2 2 3
, RANK() OVER(PARTITION BY mem_id ORDER BY createtime desc) AS RANK_desc_pv3 -- 1 2 2 4
FROM table_1
ORDER BY createtime
;-- ntile(10) over ( partition by t1.grp_cd order by t1.pay_amt desc ) Monyrank
WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 5 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '2' AS mem_id , 6 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 7 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, createtime
, ntile(3) OVER(PARTITION BY mem_id ORDER BY createtime ) AS ntile_pv1
, ntile(3) OVER(PARTITION BY score ORDER BY createtime ) AS ntile_pv2
, ntile(3) OVER(PARTITION BY mem_id ORDER BY score ) AS ntile_pv3
FROM table_1
;-- datediff(from_unixtime(unix_timestamp('${hivevar:statis_date}','yyyyMMdd'),'yyyy-MM-dd'), from_unixtime(unix_timestamp(statis_date,'yyyyMMdd'),'yyyy-MM-dd') ) as date_flag
-- pow(2, date_flag ) AS data_flag
-- conv(CAST(SUM(data_flag ) AS int),10,2) AS continuity_flag
-- locate('0',REVERSE(continuity_flag)) AS continuity_locate,
-- length(continuity_flag) AS continuity_len
-- CASE WHEN continuity_locate= 0 then continuity_len ELSE continuity_locate-1 END AS con_pv_day,-- 序列函数不支持WINDOW子句
CUME_DIST -- 小于等于当前值的行数/分组内总行数 -- 统计小于等于当前薪水的人数,所占总人数的比例
PERCENT_RANK -- 分组内当前行的RANK值-1/分组内总行数-1WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 5 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, createtime
, ROW_NUMBER() OVER(PARTITION BY mem_id ORDER BY createtime ) AS ROW_NUMBER_pv1 -- 1 2 3 4
, RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS RANK_pv3 -- 1 2 2 4
, CUME_DIST() OVER(PARTITION BY mem_id ORDER BY createtime ) AS ROW_NUMBER_desc_pv1 -- 小于等于当前值的行数/分组内总行数
, PERCENT_RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS DENSE_RANK_desc_pv2 -- 分组内当前行的RANK值-1/分组内总行数-1
FROM table_1
ORDER BY createtime
;--1.LEAD(col,n,DEFAULT) 用于统计窗口内往下第n行值-- 第一个参数为列名,第二个参数为往下第n行(可选,默认为1,不可为负数),第三个参数为默认值(当往下第n行为NULL时候,取默认值,如不指定,则为--2.LAG(col,n,DEFAULT) 用于统计窗口内往上第n行值-- 第一个参数为列名,第二个参数为往上第n行(可选,默认为1,不可为负数),第三个参数为默认值(当往上第n行为NULL时候,取默认值,如不指定,则为NULL)WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '2' AS mem_id , 6 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 7 AS score , '2020-08-07 09:09:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 9 AS score , '2020-08-09 09:08:10' AS createtime
)
select mem_id
,createtime
,score
,lead(score,2) over (partition by mem_id order by createtime) as lead_2_pv
,lead(score,1) over (partition by mem_id order by createtime) as lead_1_pv -
,lead(score,1,-9999) over (partition by mem_id order by createtime) as lead_1_null_pv
,LAG (score,1,-9999) over (partition by mem_id order by createtime) as lag_1_pv -- 统计窗口内往上第n行值
FROM table_1
;WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '2' AS mem_id , 6 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 7 AS score , '2020-08-07 09:09:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 9 AS score , '2020-08-09 09:08:10' AS createtime
)
select
mem_id
,createtime
,score
,LAG (score,2,-9999) over (partition by mem_id order by createtime) as lag_1_pv
,LAG (score,1,-9999) over (partition by mem_id order by createtime desc) as lag_1_desc_pv
,LAG (score,1) over (partition by mem_id order by createtime desc) as lag_1_desc_pv
,LAG (createtime,1,-9999) over (partition by mem_id order by createtime) as lag_1_pv
,LAG (createtime,1,-9999) over (partition by mem_id order by createtime desc) as lag_1_desc_pv -- -- 统计窗口内往上第n行值
FROM table_1
order by mem_id,createtime
;-- FIRST_VALUE取分组内排序后,截止到当前行,第一个值,
-- 需要两个参数。第一个参数是您想要第一个值的列,第二个(可选)参数必须是false默认为布尔值的布尔值。如果设置为true,则跳过空值。
-- LAST_VALUE取分组内排序后,截止到当前行,最后一个值,
-- 需要两个参数。第一个参数是您想要第一个值的列,第二个(可选)参数必须是false默认为布尔值的布尔值。如果设置为true,则跳过空值。
WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime
UNION ALL
SELECT '2' AS mem_id , 6 AS score, '2020-08-07 09:08:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 7 AS score , '2020-08-07 09:09:10' AS createtime
UNION ALL
SELECT '3' AS mem_id , 9 AS score , '2020-08-09 09:08:10' AS createtime
)
SELECT
mem_id
, score
, createtime
, ROW_NUMBER() OVER(PARTITION BY mem_id ORDER BY createtime ) AS ROW_NUMBER_pv1 -- 1 2 3 4
, DENSE_RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS DENSE_RANK_pv2 -- 1 2 2 3
, RANK() OVER(PARTITION BY mem_id ORDER BY createtime ) AS RANK_pv3 -- 1 2 2 4
, FIRST_VALUE(score) OVER(partition by mem_id order by createtime) as first1
, LAST_VALUE(score) OVER(partition by mem_id order by createtime) as last1 -- 分组内排序后,截止到当前行,最后一个值
FROM table_1
ORDER BY createti-- 多行转一行 hive collect_set 结果顺序不一致
--- concat_ws、collect_set
WITH table_1 AS(
SELECT '1' AS mem_id , 10 AS score, '2020-08-07 09:08:10' AS createtime, '10ab' AS topic_id
UNION ALL
SELECT '1' AS mem_id , 2 AS score , '2020-08-08 09:08:10' AS createtime, '2hb' AS topic_id
UNION ALL
SELECT '1' AS mem_id , 3 AS score , '2020-08-09 09:08:10' AS createtime, '3fg' AS topic_id
UNION ALL
SELECT '2' AS mem_id , 6 AS score, '2020-08-07 09:08:10' AS createtime, '6sf' AS topic_id
UNION ALL
SELECT '3' AS mem_id , 7 AS score , '2020-08-07 09:09:10' AS createtime, '7dr' AS topic_id
UNION ALL
SELECT '3' AS mem_id , 9 AS score , '2020-08-09 09:08:10' AS createtime, '9ng' AS topic_id
)
SELECT
mem_id
, concat_ws(',',collect_list(score)) as order_value
, concat_ws(',',sort_array(collect_list(score))) as order_value
, collect_list( concat_ws(':',lpad(cast(score as string),5,'0'),cast(topic_id as string)) ) AS demo1
, sort_array( collect_list( concat_ws(':',lpad(cast(score as string),5,'0'),cast(topic_id as string)) )) AS demo2
,concat_ws(',', sort_array( collect_list( concat_ws(':',lpad(cast(score as string),5,'0'),cast(topic_id as string))) ) ) AS demo3
, regexp_replace(
concat_ws(',',
sort_array(
collect_list(
concat_ws(':',lpad(cast(score as string),5,'0'),cast(topic_id as string))) ) ),'\\d+\:','') AS data
FROM table_1
group by mem_id-- 一行转多行 select explode(map_col) as (may_key_col, may_value_col) from table_name
-- posexplode 相比在 explode 之上,将一列数据转为多行之后,还会输出数据的下标
WITH table_1 AS(
select "1" AS class_id,split('Test400|Test531|Test536','\\|') AS stu_id, split('60|30|90','\\|') AS score
UNION ALL
select "2" AS class_id,split('Test400|Test531|Test536','\\|') AS stu_id, split('70|60|70','\\|') AS score
UNION ALL
select "3" AS class_id,split('Test500|Test521|Test536','\\|') AS stu_id, split('70|60|70','\\|') AS score
)
SELECT class_id,stu_id,examples_id1
FROM table_1
LATERAL VIEW explode(stu_id) examples as examples_id1
;-- 一行转多行 两列的匹配 --
WITH table_1 AS(
select "1" AS class_id,split('Test400|Test531|Test536','\\|') AS stu_id, split('60|30|90','\\|') AS score
UNION ALL
select "2" AS class_id,split('Test400|Test531|Test536','\\|') AS stu_id, split('70|60|70','\\|') AS score
UNION ALL
select "3" AS class_id,split('Test500|Test521|Test536','\\|') AS stu_id, split('70|60|70','\\|') AS score
)
SELECT class_id,sn_name,sn_score
FROM table_1
lateral view posexplode(stu_id ) sn as sn_index ,sn_name
lateral view posexplode(score ) sc as sc_index ,sn_score
WHERE sc_index = sn_index;-- 行转列
WITH table_1 AS(
SELECT '1' AS mem_id , "开心" AS tagtype, '2020-08-07 09:08:10' AS createtime, '10ab' AS topic_id
UNION ALL
SELECT '1' AS mem_id , "开心" AS tagtype , '2020-08-08 09:08:10' AS createtime, '2hb' AS topic_id
UNION ALL
SELECT '1' AS mem_id , "有趣" AS tagtype , '2020-08-09 09:08:10' AS createtime, '3fg' AS topic_id
UNION ALL
SELECT '2' AS mem_id , "有趣" AS tagtype, '2020-08-07 09:08:10' AS createtime, '6sf' AS topic_id
UNION ALL
SELECT '3' AS mem_id , "开心" AS tagtype , '2020-08-07 09:09:10' AS createtime, '7dr' AS topic_id
UNION ALL
SELECT '3' AS mem_id , "抗压" AS tagtype , '2020-08-09 09:08:10' AS createtime, '9ng' AS topic_id
)
select mem_id
,case when tagtype='有趣' then "1" else '0' end as import_fun
,case when tagtype='开心' then "1" else '0' end as import_status
,case when tagtype='抗压' then "1" else '0' end as import_chara
,createtime
,topic_id
from table_1
;---纵表变横表
-- 字段 userid flag
'张三' AS userid,'收藏' AS flag
'张三' AS userid,'购买' AS flag
'张三' AS userid,'点击' AS flag
'李四' AS userid,'点击' AS flag
'李四' AS userid,'收藏' AS flag
--结果数据
userid collction purchase click
'张三','1','1','1'
'李四','1','0','1'
--解决方案
-- 使用两种解决方案--使用union之后max
WITH t1 AS (
SELECT '张三' AS userid,'收藏' AS flag
UNION ALL
SELECT '张三' AS userid,'购买' AS flag
UNION ALL
SELECT '张三' AS userid,'点击' AS flag
UNION ALL
SELECT '李四' AS userid,'点击' AS flag
UNION ALL
SELECT '李四' AS userid,'收藏' AS flag
)
SELECT tt1.userid
, MAX(tt1.collction) AS collction
, MAX(tt1.purchase) AS purchase
, MAX(tt1.click) AS click
FROM
(SELECT
t1.userid, '1' AS collction ,'0' AS purchase, '0' AS click
FROM t1
WHERE t1.flag='收藏'
UNION ALL
select
t1.userid, '0' AS collction ,'1' AS purchase, '0' AS click
FROM t1
WHERE t1.flag='购买'
UNION ALL
select
t1.userid, '0' AS collction ,'0' AS purchase, '1' AS click
FROM t1
WHERE t1.flag='点击')tt1
GROUP BY tt1.userid
;
--使用left join的方式
WITH t1 AS (
SELECT '张三' AS userid,'收藏' AS flag
UNION ALL
SELECT '张三' AS userid,'购买' AS flag
UNION ALL
SELECT '张三' AS userid,'点击' AS flag
UNION ALL
SELECT '李四' AS userid,'点击' AS flag
UNION ALL
SELECT '李四' AS userid,'收藏' AS flag
)
SELECT
tt1.userid,
CASE WHEN tt2.userid IS NOT NULL then'1' ELSE '0'END AS collction,
CASE WHEN tt3.userid IS NOT NULL then'1' ELSE '0'END AS purchase,
CASE WHEN tt4.userid IS NOT NULL then'1' ELSE '0'END AS click
FROM (SELECT DISTINCT t1.userid FROM t1)tt1
LEFT JOIN (SELECT DISTINCT t1.userid FROM t1 WHERE t1.flag = '收藏')tt2
ON tt1.userid = tt2.userid
LEFT JOIN (SELECT DISTINCT t1.userid FROM t1 WHERE t1.flag = '购买')tt3
ON tt1.userid = tt3.userid
LEFT JOIN (SELECT DISTINCT t1.userid FROM t1 WHERE t1.flag = '点击')tt4
ON tt1.userid = tt4.userid--多列转一列 横表变纵表,列转行
WITH table_1 AS (
SELECT "张三" AS userid, '1' AS collction ,'1' AS purchase, '1' AS click
UNION ALL
"张三" AS userid, '0' AS collction ,'1' AS purchase, '1' AS click)
SELECT
from
(SELECT userid,'收藏' AS flag FROM table_1 WHERE collction='1'
UNION ALL
SELECT userid,'购买' AS flag FROM table_1 WHERE purchase='1'
UNION ALL
SELECT userid,'点击' AS flag FROM table_1 WHERE click='1')t1
本次分享主要是涉及开窗函数以及行列的一些开发内容。后续的一些内容,也是应用开发中的一些比较常见的要注意和区分的点。
本示例参考了一些网上的资料和书本的内容,由于来源未做标记,如有侵删。
Hive 高阶应用开发示例(一)的更多相关文章
- Hive高阶聚合函数 GROUPING SETS、Cube、Rollup
-- GROUPING SETS作为GROUP BY的子句,允许开发人员在GROUP BY语句后面指定多个统计选项,可以简单理解为多条group by语句通过union all把查询结果聚合起来结合起 ...
- hive高阶1--sql和hive语句执行顺序、explain查看执行计划、group by生成MR
hive语句执行顺序 msyql语句执行顺序 代码写的顺序: select ... from... where.... group by... having... order by.. 或者 from ...
- 聊聊React高阶组件(Higher-Order Components)
使用 react已经有不短的时间了,最近看到关于 react高阶组件的一篇文章,看了之后顿时眼前一亮,对于我这种还在新手村晃荡.一切朝着打怪升级看齐的小喽啰来说,像这种难度不是太高同时门槛也不是那么低 ...
- Swift 烧脑体操(三) - 高阶函数
前言 Swift 其实比 Objective-C 复杂很多,相对于出生于上世纪 80 年代的 Objective-C 来说,Swift 融入了大量新特性.这也使得我们学习掌握这门语言变得相对来说更加困 ...
- Javascript 常见的高阶函数
高阶函数,英文叫 Higher Order function.一个函数可以接收另外一个函数作为参数,这种函数就叫做高阶函数. 示例: function add(x, y, f) { return f( ...
- JavaScript设计模式与开发实践——读书笔记1.高阶函数(下)
上部分主要介绍高阶函数的常见形式,本部分将着重介绍高阶函数的高级应用. 1.currying currying指的是函数柯里化,又称部分求值.一个currying的函数会先接受一些参数,但不立即求值, ...
- JavaScript设计模式与开发实践——读书笔记1.高阶函数(上)
说来惭愧,4个多月未更新了.4月份以后就开始忙起来了,论文.毕设.毕业旅行等七七八八的事情占据了很多时间,毕业之后开始忙碌的工作,这期间一直想写博客,但是一直没能静下心写.这段时间在看<Java ...
- Python开发【第十三篇】高阶函数、递归函数、闭包
函数式编程是指用一系列函数解决问题 好处:用每个函数完成每个细小的功能,一系列函数任意组合能够解决大问题 函数仅仅接收输入并产生输出,不包含任何能影响输出的内部状态 函数之间的可重入性 当一个函数的输 ...
- python开发基础04-函数、递归、匿名函数、高阶函数、装饰器
匿名函数 lamba lambda x,y,z=1:x+y+z 匿名就是没有名字 def func(x,y,z=1): return x+y+z 匿名 lambda x,y,z=1:x+y+z #与函 ...
随机推荐
- Python使用Tornado+Redis维护ADSL拨号服务器代理池
们尝试维护过一个免费的代理池,但是代理池效果用过就知道了,毕竟里面有大量免费代理,虽然这些代理是可用的,但是既然我们能刷到这个免费代理,别人也能呀,所以就导致这个代理同时被很多人使用来抓取网站,所以当 ...
- 改改Python代码,运行速度还能提升6万倍
这份最新研究指出,在后摩尔定律时代,人类所获得的的算力提升将更大程度上来源于计算堆栈的「顶层」,即软件.算法和硬件架构,这将成为一个新的历史趋势. 很多人学习python,不知道从何学起.很多人学习p ...
- CSS漂亮盒子(上)
HTML文档中的所有元素都是由矩形盒子构成的--不管是包含页面结构的容器元素,还是段落中的每行文本,归根结底都是盒子. 1.背景颜色 设置页面背景颜色. body { background-color ...
- 解决Android v4、v7包导入标红问题import android.support.v4.app.ActivityCompat;import android.support.v7.app
如果有如下错误:import android.support.v4.app.ActivityCompat;import android.support.v7.app.AppCompatActivity ...
- 2020-05-24:ZK分布式锁有几种实现方式?各自的优缺点是什么?
福哥答案2020-05-24: Zk分布式锁有两种实现方式一种比较简单,应对并发量不是很大的情况.获得锁:创建一个临时节点,比如/lock,如果成功获得锁,如果失败没获得锁,返回false释放锁:删除 ...
- 靶机练习 - ATT&CK红队实战靶场 - 1. 环境搭建和漏洞利用
最近某个公众号介绍了网上的一套环境,这个环境是多个Windows靶机组成的,涉及到内网渗透,正好Windows和内网渗透一直没怎么接触过,所以拿来学习下. 下载地址:http://vulnstack. ...
- Deep Learning-Based Document Modeling for Personality Detection from Text 阅读笔记
文章目录 代码地址 1. 摘要 2. 方法综述 2.1 输入信息预处理 2.2 文档层面的格式特征提取 2.3 数据过滤 2.4 单词层面上的特征提取 2.5分类 3. 分类网络结构 3.1 步骤 3 ...
- POJ2806 Square
题目描述 给定\(2*1\)和\(2 * 2\)两种规格的地砖,请问\(2 * n\)的地面总共有多少种方法? 下面是铺满\(2*17\)的地面的示意图. 输入输出格式 输入 多组数据,每组数据包括1 ...
- 分治算法(二分查找)、STL函数库的应用第五弹——二分函数
分治算法:二分查找!昨天刚说不写算法了,但是突然想起来没写过分治算法的博客,所以强迫症的我…… STL函数库第五弹——二分函数lower_bound().upper_bound().binary_se ...
- python3 - 常用的操作数据库
# 获取手机号数据表的中的数据 sql2 = 'SELECT shoujihao FROM shoujihao' self.cursor.execute(sql2) sjh_dates = self. ...