import matplotlib.pyplot as plt         # for my tests version 3.3.2
import numpy as np

# Creating dataset
np.random.seed(42)
x = np.random.random_sample(size=10000)
y = np.random.random_sample(size=10000)
z = np.random.random_sample(size=10000)

# Creating figure
fig = plt.figure(figsize=(16, 9))
ax = plt.axes(projection="3d")

# Add x, y gridlines
ax.grid(b=True, color='grey', linestyle='-.', linewidth=0.3, alpha=0.2)

# Creating color map
# https://matplotlib.org/3.1.0/tutorials/colors/colormaps.html
my_cmap = plt.get_cmap('brg')

# Creating plot
sctt = ax.scatter3D(x, y, z, alpha=0.8, c=z, cmap=my_cmap, marker='o')

plt.title("3D-Scatter")
ax.set_xlabel('x label', fontweight='bold')
ax.set_ylabel('y label', fontweight='bold')
ax.set_zlabel('z label', fontweight='bold')
fig.colorbar(sctt, ax=ax, shrink=0.5, aspect=5)

# show plot
plt.show()
# plt.savefig('fig_savefig.png')
plt.close()