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What is SQRT() function in Apache Pig ?

  • The SQRT() function is used to calculate the square root of a given expression.
  • The SQRT function is a built-in function in Excel that is categorized as a Math/Trig Function.
  • It can be used as a worksheet function (WS) in Excel.

Syntax

grunt> SQRT(expression)

Example

  • Ensure that that we have a file named wikitechy_math.txt in the HDFS directory /pig_data/. This file contains integer and floating point values as given below.

wikitechy_math.txt

5 
16 
9 
2.5 
5.9 
3.1 
  • We have loaded this file into Pig with a relation named wikitechy_math_data as given below
grunt> math_data = LOAD 'hdfs://localhost:9000/pig_data/wikitechy_math.txt' USING PigStorage(',')
   as (data:float);
  • Now you can generate the square root values of the contents of the wikitechy_math.txt file using SQRT() function as given below.
grunt> sqrt_data = foreach math_data generate (data), SQRT(data);

Verification

  • Verify the contents of the relation using the Dump operator as given below.
grunt> Dump sqrt_data;

Output

  • The above statement stores the result in the relation named sqrt_data.
  
(5.0,2.23606797749979) 
(16.0,4.0) 
(9.0,3.0) 
(2.5,1.5811388300841898) 
(5.9,2.4289915799292987) 
(3.1,1.76068165908337) 

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