pig中使用的一些实例语法

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在pig中， dump和store会分别完毕两个MR， 不会一起进行

1：载入名用正則表達式：

LOAD ‘/user/wizad/data/wizad/raw/2014-0{6,7-0,7-1,7-2,7-3,8}*/3_1/adwords*’

2：filter的几种简单使用方法：

按值过滤

FILTER clickDate_all BY log_type==’2′; FILTER mapping_table BY mapping_ad_network_id==’3′ AND mapping_type==’5′; test =FILTER allRow BY (ad_id==’14997′ OR ad_id==’14998′ OR ad_id==’14999′) AND log_type==2; test=FILTER allRow BY (INDEXOF(ad_id,’14997′)==0 OR INDEXOF(ad_id,’14998′)==0 OR INDEXOF(ad_id,’14999′)==0) AND log_type==2;

配合size函数

FILTER count_imei BY (SIZE(cimei)>14 AND SIZE(cimei)<17);

正則表達式

FILTER cimei2 BY NOT cimei MATCHES ‘^[0-9]*$’; FILTER cmac2 BY cmac MATCHES ‘/[A-F\d]{2}:[A-F\d]{2}:[A-F\d]{2}:[A-F\d]{2}:[A-F\d]{2}:[A-F\d]{2}/’;

3：排序

ORDER province_count BY $2 DESC;

4：CONCAT函数的使用。可用于生成独立的一列，如count了的一个数，前面加一列名称 FOREACH origin_cleaned_data GENERATE CONCAT(‘<-_’,’->’) AS cou,guid,log_type; read_social_14 =FOREACH metadata_social_14 GENERATE CONCAT(’14’,’==’),guid_social; all_id =FOREACH allRow GENERATE id,CONCAT(‘_’,’-‘) as cc;

5：过滤空值，将空值改成取值unknown。

     条件表达式“（推断式）？a：b”的应用：直接对列操作

origin_historical = FOREACH origin_cleaned_data GENERATE wizad_ad_id,guid,log_type, ((province_region_id == ”) ? ‘unknown’ : province_region_id)

6:切分成不同子集，按值：  SPLIT geelyTuiGuang INTO android IF os_id==1,ios IF os_id==2;  SPLIT ios INTO ios6 IF (INDEXOF(os_version,’7′)!=0),ios7 IF INDEXOF(os_version,’7′)==0;

SPLIT allCleaned INTO log_42 IF ( ((chararray)$34==’1′ OR (chararray)$34==’2′ OR (chararray)$34==’3′ OR (chararray)$34==’1′ OR (chararray)$34==’4′) AND (INDEXOF((chararray)$35,’.’)>0) AND ((chararray)$36==’1′ OR (chararray)$36==”)

), log_43 IF ( ((chararray)$34==’1′ OR (chararray)$34==’2′) AND ((chararray)$35==’1′ OR (chararray)$35==’2′ OR (chararray)$35==’3′ OR (chararray)$35==’1′ OR (chararray)$35==’4′) AND (INDEXOF((chararray)$36,’.’)>0) );

7：replace函数替换值  FOREACH ios6 GENERATE imei,mac_address as cmac,REPLACE(idfa,’null’,”);

8：数据流过滤

 en_guid =STREAM duimei THROUGH `awk -F”,” ‘{if($3 == “null”) print $1″,”$2″,”; else print $0}’`;

9：强制转换：

cleaned_data_42 =FOREACH log_42 GENERATE  (chararray)$1  AS wizad_ad_id:chararray, (chararray)$2  AS guid:chararray, (chararray)$6  AS log_type:chararray, (chararray)$18 AS imei:chararray, (chararray)$22 AS idfa:chararray, (chararray)$23 AS mac_address:chararray

10内置函数REGEX_EXTRACT，使用正則表達式：

allAdId =FOREACH allRow GENERATE REGEX_EXTRACT((chararray)$3,'(.*) (.*)’,1) AS time,REGEX_EXTRACT((chararray)$0,'(.*)_(.*)’,1) AS adn,$6 AS ad_id;

 allAdId =FOREACH allRow GENERATE REGEX_EXTRACT(create_time,'(.*) (.*)’,1) AS time,ad_id;

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