问如何在matplotlib上为3D绘图绘制单独的线条

EN

import matplotlib.pyplot as plt
import numpy as np

# Create numpy arrays
xs = np.array([1,1,1,2,2,2,3,3,3])
ys = np.array([1,2,3,1,2,3,1,2,3])
zs = np.array([1,4,9,2,8,18,4,16,36])

# Create Figure and 3D Axes
fig = plt.figure()
ax = fig.add_subplot(projection='3d')

# Iterate over unique values in xs array
for unique_x in np.unique(xs):
    # Slice arrays and plot
    xvals = xs[np.where(xs == unique_x)]
    yvals = ys[np.where(xs == unique_x)]
    zvals = zs[np.where(xs == unique_x)]
    ax.plot3D(xvals, yvals, zvals)

# Display Figure
plt.show()