What is the purpose of the SPLIT statement in Pig?

The SPLIT statement in Apache Pig is used to divide a dataset (relation) into multiple parts based on specified conditions. Specifically, the SPLIT statement can partition data into different data streams based on the value of a column or the result of an expression. This is commonly used in data processing and analysis for categorizing, filtering, or splitting data.

Here is the basic syntax of the SPLIT statement:

split_data = SPLIT data INTO output1 IF condition1, output2 IF condition2, ...;

1. Data: The dataset (relationship) to be segmented.
2. Output sections generated based on conditions.
3. Conditions 1, 2, etc. are used to specify how the data should be segmented.

For example, let’s say we have a dataset containing employee information. We can use the SPLIT function to divide the data into two parts based on the employees’ salary levels: high and low salaries.

employee_data = LOAD 'employee_data.csv' USING PigStorage(',') AS (name:chararray, salary:int);

split_employee = SPLIT employee_data INTO high_salary IF salary >= 5000, low_salary IF salary < 5000;

DESCRIBE split_employee;
DUMP high_salary;
DUMP low_salary;

Based on the examples above, SPLIT will divide the data into two parts, high salary and low salary, based on whether the employee’s salary is greater than or equal to 5000, and store the results in two variables, high_salary and low_salary.