我想從XML輸入中提取使用Hadoop豬拉丁文

Question

的特定信息預期輸出爲：(Hadoop definitive guide,Tom white,24.90)。

我試過使用Regex_Extract()函數。但是，沒有運氣。有人可以幫我嗎？

輸入到我的腳本是：

<CATALOG> 
<BOOK> 
<TITLE>Hadoop DEFINITIVE GUIDE</TITLE> 
<AUTHOR>TOM WHITE</AUTHOR> 
<COUNTRY>US</COUNTRY> 
<COMPANY>CLOUDERA</COMPANY> 
<PRICE>24.90</PRICE> 
<YEAR>2012</YEAR> 
</BOOK> 
<BOOK> 
<TITLE>Programming Pig</TITLE> 
<AUTHOR>Alan Gates</AUTHOR> 
<COUNTRY>USA</COUNTRY> 
<COMPANY>Horton Works</COMPANY> 
<PRICE>30.90</PRICE> 
<YEAR>2013</YEAR> 
</BOOK> 
</CATALOG> 

Answer 1

你將不得不提取<TITLE>，<AUTHOR>和<PRICE>分開，然後用JOIN運營商加入他們在一起。

下面的腳本實現了：

-- Load input 
A = LOAD '/input.txt' USING PigStorage() AS (f1:chararray); 

-- Extract <TITLE> 
B1 = FOREACH A GENERATE REGEX_EXTRACT(f1, '<TITLE>(.*)</TITLE>', 1) AS (title:chararray); 
C1 = FILTER B1 BY title is not null; 
D1 = RANK C1; 

-- Extract <AUTHOR> 
B2 = FOREACH A GENERATE REGEX_EXTRACT(f1, '<AUTHOR>(.*)</AUTHOR>', 1) AS (author:chararray); 
C2 = FILTER B2 BY author is not null; 
D2 = RANK C2; 

-- Extract <PRICE> 
B3 = FOREACH A GENERATE REGEX_EXTRACT(f1, '<PRICE>(.*)</PRICE>', 1) AS (price:chararray); 
C3 = FILTER B3 BY price is not null; 
D3 = RANK C3; 

-- Join 3 data sets 
D = JOIN D1 BY $0, D2 BY $0, D3 By $0; 

-- Eliminate the ranks 
E = FOREACH D GENERATE $1 AS (title:chrarray), $3 AS (author:chararray), $5 AS (price:chararray) 

dump E; 

對於問題中提及的投入，我得到了以下的輸出：

(Hadoop DEFINITIVE GUIDE,TOM WHITE,24.90) 
(Programming Pig,Alan Gates,30.90)