Apache Pig - ToString()

This method is used to convert the date-time object to a customized string.

Syntax

Here is the syntax of the ToString() function.

grunt> ToString(datetime [, format string])

Example

Assume that there is a file named date.txt in the HDFS directory /pig_data/. This file contains the date-of-birth details of a particular person, id, date, and time.

date.txt

001,1989/09/26 09:00:00
002,1980/06/20 10:22:00
003,1990/12/19 03:11:44

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

grunt> date_data = LOAD 'hdfs://localhost:9000/pig_data/date.txt' USING PigStorage(',')
   as (id:int,date:chararray);

Following is an example of the ToString() function. The ToString() function converts the given date-time objects in to String format. Therefore, let us generate the date-time objects of all employees using todate() function.

grunt> todate_data = foreach date_data generate ToDate(date,'yyyy/MM/dd HH:mm:ss')
   as (date_time:DateTime ); 
 
grunt> Dump todate_data;
(1989-09-26T09:00:00.000+05:30) 
(1980-06-20T10:22:00.000+05:30) 
(1990-12-19T03:11:44.000+05:30)

Let us get the string format of the date-time objects of all the employees using ToString() method and store it in a relation named tostring_data.

grunt> tostring_data = foreach todate_data generate (date_time), ToString(date_time,Text);

Verify the tostring_data relation using the Dump command as shown below.

grunt> Dump tostring_data;
  
(1989-09-26T09:00:00.000+05:30,39) 
(1980-06-20T10:22:00.000+05:30,25) 
(1990-12-19T03:11:44.000+05:30,51)