multiple y axes in scatter plot code example

Example 1: multiple scatter plots in python

import matplotlib.pyplot as plt

x = range(100)
y = range(100,200)
fig = plt.figure()
ax1 = fig.add_subplot(111)

ax1.scatter(x[:4], y[:4], s=10, c='b', marker="s", label='first')
ax1.scatter(x[40:],y[40:], s=10, c='r', marker="o", label='second')
plt.legend(loc='upper left');
plt.show()

Example 2: how can I plot 3 variables in pyplot.scatter

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np

x = np.random.rand(20)
y = np.random.rand(20)
z = x*y

fig = plt.figure(figsize=(6, 6))
ax = fig.add_subplot(111, projection='3d')
ax.scatter(x, y, z, linewidths=1, alpha=.7, edgecolor='k', s = 200, c=z)
plt.show()