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)