How to create a legend for a 3D bar in Matplotlib?

To create a legend for a 3D bar in matplotlib, we can plot 3D bars and place a legend using legend() method.

Steps

Set the figure size and adjust the padding between and around the subplots.
Create a new figure or activate an esxisting figure using figure() method.
Add an axes to the figure as part of a subplot arrangement.
Create a list of data x3, y3, z3, dx, dy and dz using numpy.
Plot a 3D bar using bar3d() method.
Create a rectangle axis for legend placement.
Use legend() method to place the legend for bars.
To display the figure, use show() method.

Example

import numpy as np
from matplotlib import pyplot as plt
plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True
fig = plt.figure()
ax1 = fig.add_subplot(111, projection='3d')
x3 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
y3 = [5, 6, 7, 8, 2, 5, 6, 3, 7, 2]
z3 = np.zeros(10)
dx = np.ones(10)
dy = np.ones(10)
dz = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
ax1.bar3d(x3, y3, z3, dx, dy, dz, color="green")
b1 = plt.Rectangle((0, 0), 1, 1, fc="green")
ax1.bar3d(y3, x3, z3, dx, dy, dz, color="red")
b2 = plt.Rectangle((0, 0), 1, 1, fc="red")
ax1.legend([b1, b2], ['type1', 'type2'])
plt.show()