Apache Pig - COS()
The COS() function of Pig Latin is used to calculate the cosine value of a given expression.
Here is the syntax of the COS() function.
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.
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)
Now, let’s calculate the cosine values of the contents of the math.txt file using COS() function as shown below.
grunt> cos_data = foreach math_data generate (data), COS(data);
The above statement stores the result in the relation named cos_data. Verify the contents of the relation using the Dump operator as shown below.
grunt> Dump cos_data; (5.0,0.28366218546322625) (16.0,-0.9576594803233847) (9.0,-0.9111302618846769) (2.5,-0.8011436155469337) (5.9,0.9274784663996888) (3.1,-0.999135146307834)