Python script to compute regression line.

regression_line.py

#! /usr/local/bin/python3.6
"""
Computation of a simple lenear regression line
"""
import sys
import traceback


class RegressionLine:
    def reg_line(self, x, y):
        """ Regression line computation

        :param  list  x: 1st list of variables
        :param  list  y: 2nd list of variables
        :return list [a, b]: a = intercept, b = slope
        """
        try:
            if type(x) != list:
                print("Argument(X) is not a list!")
                sys.exit()
            if type(y) != list:
                print("Argument(Y) is not a list!")
                sys.exit()
            if len(x) == 0:
                print("List(X) is none!")
                sys.exit()
            if len(y) == 0:
                print("List(Y) is none!")
                sys.exit()
            if len(x) != len(y):
                print("Argument list size is invalid!")
                sys.exit()
            sum_x, sum_y = sum(x), sum(y)
            sum_xx = sum([a * a for a in x])
            sum_xy = sum([a * b for a, b in zip(x, y)])
            a  = sum_xx * sum_y - sum_xy * sum_x
            a /= len(x) * sum_xx - sum_x * sum_x
            b  = len(x) * sum_xy - sum_x * sum_y
            b /= len(x) * sum_xx - sum_x * sum_x
            return [a, b]
        except Exception as e:
            raise


if __name__ == '__main__':
    try:
        x = [107, 336, 233, 82, 61, 378, 129, 313, 142, 428]
        y = [286, 851, 589, 389, 158, 1037, 463, 563, 372, 1020]
        print("説明変数 X =", x)
        print("目的変数 Y =", y)
        print("---")
        obj = RegressionLine()
        reg_line = obj.reg_line(x, y)
        print("切片 a =", reg_line[0])
        print("傾き b =", reg_line[1])
    except Exception as e:
        traceback.print_exc()
        sys.exit(1)