RANDOMIZED DATA POINTS IN Matplotlib

Listing 5.13 displays the contents of lin_reg_plot.py that illustrates how to plot a graph of random points.

LISTING 5.13: lin_plot_reg.py

import numpy as np
import matplotlib.pyplot as plt

trX = np.linspace(-1, 1, 101) # Linear space of 101 and [-1,1]

#Create the y function based on the x axis
trY = 2*trX + np.random.randn(*trX.shape)*0.4+0.2

#create figure and scatter plot of the random points
plt.figure()
plt.scatter(trX,trY)

# Draw one line with the line function
plt.plot (trX, .2 + 2 * trX)
plt.show()  

Listing 5.13 defines the NumPy variable trX that contains 101 equally spaced numbers that are between -1 and 1 (inclusive). The variable trY is defined in two parts: the first part is 2*trX and the second part is a random value that is partially based on the length of the one-dimensional array trX. The variable trY is the sum of these two “parts,” which creates a “fuzzy” line segment.

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