# Measure information gain / loss after a data Transformation operation [closed]

Suppose that we have a dataset of 2 samples :

 [{1,2,0}, {2,0,0}, {3,1,1}, {4,0,1}, {5,1,1}]


(the last element of each row is the class variable)

If we want to reduce the variety of the column "1" we can put all values that are less or equal to "2" to a new value "1" and values that are greater than "2" to the value 2, so we would have a new dataset like :

[{1,2,0}, {1,0,0}, {2,1,1}, {2,0,1}, {2,1,1}]


In this example we can easly deduct that there is a information gain after this transfromation, but what if we have million of sample, is there any way to measure the information gain / loss after such a transformation.