Apache Pig - ATAN()

The ATAN() function of Pig Latin is used to calculate the arc tan value of a given expression.

Syntax

Here is the syntax of the ATAN() function.

grunt> ATAN(expression)

Example

Assume that there is a file named math.txt in the HDFS directory /pig_data/. This file contains integer and floating point values as shown below.

math.txt

5 
16 
9 
2.5 
5.9 
3.1 

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

grunt> math_data = LOAD 'hdfs://localhost:9000/pig_data/math.txt' USING PigStorage(',')
   as (data:float);

Let us now calculate the arc tan values of the contents of the math.txt file using ATAN() function as shown below.

grunt> atan_data = foreach math_data generate (data), ATAN(data);

The above statement stores the result in the relation named asin_data. Verify the contents of the relation using the Dump operator as shown below.

grunt> Dump atan_data;
  
(5.0,1.373400766945016) 
(16.0,1.5083775167989393) 
(9.0,1.460139105621001) 
(2.5,1.1902899496825317) 
(5.9,1.4029004062076729) 
(3.1,1.2587541962439153)