Answer by Selman Genç for Compare 2 byte arrays

You are looking for Zip method

var data3 = data1.Zip(data2, (d1,d2) => Math.Abs(d1 - d2)).ToArray();

Enumerable.Zip<TFirst, TSecond, TResult> Method

Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.

So it simply takes each corresponding element, e.g data1[0] and data2[0], then data1[1] and data2[1] so on.. then applies the function Math.Abs(d1-d2) which simply substracts two numbers and gets the absolute value of the result. Then returns a sequence which contains the result of each operation.