Apache Pig - STRSPLITTOBAG()


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This function is similar to the STRSPLIT() function. It splits the string by a given delimiter and returns the result in a bag.

Syntax

The syntax of STRSPLITTOBAG() is given below. This function accepts a string that is needed to be split, a regular expression, and an integer value specifying the limit (the number of substrings the string should be split). This function parses the string and when it encounters the given regular expression, it splits the sting into n number of substrings where n will be the value passed to limit.

grunt> STRSPLITTOBAG(string, regex, limit)

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_Smith,22,newyork 
002,BOB_Wilson,23,Kolkata 
003,Maya_Reddy,23,Tokyo 
004,Sara_Jain,25,London 
005,David_Miller,23,Bhuwaneshwar 
006,Maggy_Moore,22,Chennai 
007,Robert_Scott,22,newyork 
008,Syam_Ketavarapu,23,Kolkata 
009,Mary_Carter,25,Tokyo 
010,Saran_Naidu,25,London 
011,Stacy_Green,25,Bhuwaneshwar 
012,Kelly_Moore,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);

Following is an example of the STRSPLITTOBAG() function. If you observe the emp.txt file, you can find that, in the name column, we have name and surname of the employees separated by the delemeter “_”.

In this example we are trying to split the name and surname of the employee, and get the result in a bag using STRSPLITTOBAG() function.

grunt> strsplittobag_data = FOREACH emp_data GENERATE (id,name), STRSPLITTOBAG (name,'_',2);

The result of the statement will be stored in the relation named strsplittobag_data. Verify the content of the relation strsplittobag_data, using the Dump operator as shown below.

grunt> Dump strsplittobag_data;
  
((1,Robin_Smith),{(Robin),(Smith)}) 
((2,BOB_Wilson),{(BOB),(Wilson)}) 
((3,Maya_Reddy),{(Maya),(Reddy)}) 
((4,Sara_Jain),{(Sara),(Jain)}) 
((5,David_Miller),{(David),(Miller)}) 
((6,Maggy_Moore),{(Maggy),(Moore)}) 
((7,Robert_Scott),{(Robert),(Scott)}) 
((8,Syam_Ketavarapu),{(Syam),(Ketavarapu)}) 
((9,Mary_Carter),{(Mary),(Carter)})
((10,Saran_Naidu),{(Saran),(Naidu)}) 
((11,Stacy_Green),{(Stacy),(Green)}) 
((12,Kelly_Moore),{(Kelly),(Moore)}) 
apache_pig_string_functions.htm
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