# Import the plotting library
import matplotlib.pyplot as plt
# import the numerical library
import numpy as np


number_of_multiplanet_systems = 657
number_of_confirmed_planets = 3916
print("Hello World. On 14th February 2019 there are 3 917 confirmed planets.")
print("Tthe number of multi-planet systems is {:d}.".format(number_of_confirmed_planets))
print("There are {:3.2f} planets/system, on average".format(
  float(number_of_confirmed_planets)/float(number_of_multiplanet_systems)))

# Create an array of N zero elements
N = 1000
vec = np.zeros(N)

# Create an array of N linearly spaced elements from -pi to pi
phi = np.linspace(-np.pi, np.pi, N)

# Create sine and cosine vectors
x = 0.5*np.cos(phi)
y = 1.0*np.sin(phi)

# Define figure and axes
fig, (ax0, ax1) = plt.subplots(ncols=1, nrows=2, num=31415)

# Plot vectors and add decorations
ax0.plot(phi, x, color='red', label='cos(phi)')
ax0.plot(phi, y, color='blue', label='sin(ph i)')
ax0.set_xlabel("$\phi$ [rad]") # Note: labels can use Latex notation within $$ symbols
ax0.set_ylabel("Function")
ax0.grid()
ax0.legend()


ax1.plot(x, y, color='black', label='This is an ellipse')
ax1.set_xlabel("x")
ax1.set_ylabel("y")
ax1.set_xlim(-1.1, 1.1)
ax1.set_ylim(-1.1, 1.1)
ax1.grid()
ax1.legend()

plt.show()