Python, Matplotlib, Scatter plot, Change color on the clicked point

Question

I have a simple scatter plot with a picker event.
I want to change the color of the data point I click with mouse.
The code I have will change the color of the whole array.
How can I just change one particular point?

import sys
import numpy as np
import matplotlib.pyplot as plt    
testData = np.array([[0,0], [0.1, 0], [0, 0.3], [-0.4, 0], [0, -0.5]])
    fig, ax = plt.subplots()
    sctPlot, = ax.plot(testData[:,0], testData[:,1], "o", picker = 5)
    plt.grid(True)
    plt.axis([-0.5, 0.5, -0.5, 0.5])

def on_pick(event):
    artist = event.artist
    artist.set_color(np.random.random(3))
    print "click!"
    fig.canvas.draw()

fig.canvas.mpl_connect('pick_event', on_pick)

Answer 1

import sys
import numpy as np
import matplotlib.pyplot as plt

testData = np.array([[0,0], [0.1, 0], [0, 0.3], [-0.4, 0], [0, -0.5]])
fig, ax = plt.subplots()
coll = ax.scatter(testData[:,0], testData[:,1], color=["blue"]*len(testData), picker = 5, s=[50]*len(testData))
plt.grid(True)
plt.axis([-0.5, 0.5, -0.5, 0.5])

def on_pick(event):
    print testData[event.ind], "clicked"
    coll._facecolors[event.ind,:] = (1, 0, 0, 1)
    coll._edgecolors[event.ind,:] = (1, 0, 0, 1)
    fig.canvas.draw()

fig.canvas.mpl_connect('pick_event', on_pick)
plt.show()