Apache Pig - ACOS()

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

Syntax

Here is the syntax of the ACOS() function.

grunt> ACOS(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 cosine values of the contents of the math.txt file using ACOS() function as shown below.

grunt> acos_data = foreach math_data generate (data), ACOS(data);

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

grunt> Dump acos_data;
  
(5.0,NaN) 
(16.0,NaN) 
(9.0,NaN) 
(2.5,NaN) 
(5.9,NaN) 
(3.1,NaN)