"""
Ex. 5.14 from "A primer on..."
Read two columns from a file and plot the result. 
"""

import numpy as np
import matplotlib.pyplot as plt

x = []
y = []

with open('xy.txt') as infile:
    for line in infile:
        xy = line.split()
        x.append(float(xy[0]))
        y.append(float(xy[1]))

#converting to arrays makes it easier to compute mean y
x = np.array(x)
y = np.array(y)

print(f"Max y = {np.max(y)}, min y = {np.min(y)}, mean = {np.mean(y)}")

plt.plot(x,y)
plt.show()