Apache Pig - LOWER()


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This function is used to convert all the characters in a string to lowercase.

Syntax

Following is the syntax of the LOWER() function.

grunt> LOWER(expression)

Example

Assume that there is a file named emp.txt in the HDFS directory /pig_data/ as shown below. This file contains the employee details such as id, name, age, and city.

emp.txt

001,Robin,22,newyork
002,BOB,23,Kolkata
003,Maya,23,Tokyo
004,Sara,25,London 
005,David,23,Bhuwaneshwar 
006,Maggy,22,Chennai
007,Robert,22,newyork
008,Syam,23,Kolkata
009,Mary,25,Tokyo
010,Saran,25,London 
011,Stacy,25,Bhuwaneshwar 
012,Kelly,22,Chennai

And, we have loaded this file into Pig with a relation named emp_data as shown below.

grunt> emp_data = LOAD 'hdfs://localhost:9000/pig_data/emp.txt' USING PigStorage(',')
   as (id:int, name:chararray, age:int, city:chararray);

Given below is an example of the LOWER() function. In this example, we have converted the names of all the employees to lowercase.

grunt> lower_data = FOREACH emp_data GENERATE (id,name), LOWER(name);

The above statement converts the names of all the employees to lowercase and returns the result.

The result of the statement will be stored in the relation named lower_data. Verify the content of the relation lower_data, using the Dump operator.

grunt> Dump lower_data; 
 
((1,Robin),robin)
((2,BOB),bob)
((3,Maya),maya)
((4,Sara),sara)
((5,David),david) 
((6,Maggy),maggy)
((7,Robert),robert)
((8,Syam),syam)
((9,Mary),mary)
((10,Saran),saran)
((11,Stacy),stacy)
((12,Kelly),kelly)
apache_pig_string_functions.htm
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