Apache Pig - RANDOM()
The RANDOM() function is used to get a pseudo random number (type double) greater than or equal to 0.0 and less than 1.0.
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);
Let us now generate random values of the contents of the math.txt file using RANDOM() function as shown below.
grunt> random_data = foreach math_data generate (data), RANDOM();
The above statement stores the result in the relation named random_data. Verify the contents of the relation using the Dump operator as shown below.
grunt> Dump random_data; (5.0,0.6842057767279982) (16.0,0.9725172591786139) (9.0,0.4159326414649489) (2.5,0.30962777780713147) (5.9,0.705213727551145) (3.1,0.24247708413861724)