TheFOREACHoperator is used to generate specified data transformations based on the column data.

Syntax

Given below is the syntax ofFOREACHoperator.

grunt
>
 Relation_name2 = FOREACH Relatin_name1 GENERATE (required data);

Example

Assume that we have a file namedstudent_details.txtin the HDFS directory/pig_data/as shown below.

student_details.txt

001,Rajiv,Reddy,21,9848022337,Hyderabad
002,siddarth,Battacharya,22,9848022338,Kolkata
003,Rajesh,Khanna,22,9848022339,Delhi 
004,Preethi,Agarwal,21,9848022330,Pune 
005,Trupthi,Mohanthy,23,9848022336,Bhuwaneshwar 
006,Archana,Mishra,23,9848022335,Chennai 
007,Komal,Nayak,24,9848022334,trivendram 
008,Bharathi,Nambiayar,24,9848022333,Chennai

And we have loaded this file into Pig with the relation namestudent_detailsas shown below.

grunt
>
 student_details 
=
 LOAD 
'hdfs://localhost:9000/pig_data/student_details.txt'
 USING 
PigStorage
(
','
)
as
(
id
:
int
,
 firstname
:
chararray
,
 lastname
:
chararray
,
age
:
int
,
 phone
:
chararray
,
 city
:
chararray
);

Let us now get the id, age, and city values of each student from the relationstudent_detailsand store it into another relation namedforeach_datausing theforeachoperator as shown below.

grunt
>
 foreach_data 
=
 FOREACH student_details GENERATE id
,
age
,
city
;

Verification

Verify the relationforeach_datausing theDUMPoperator as shown below.

grunt
>
Dump
 foreach_data
;

Output

It will produce the following output, displaying the contents of the relationforeach_data.

(1,21,Hyderabad)
(2,22,Kolkata)
(3,22,Delhi)
(4,21,Pune) 
(5,23,Bhuwaneshwar)
(6,23,Chennai) 
(7,24,trivendram)
(8,24,Chennai)