Color axis spine with multiple colors using matplotlib

Question

Is it possible to color axis spine with multiple colors using matplotlib in python?

Desired output style:

Answer 1

You can use a LineCollection to create a multicolored line. You can then use the xaxis-transform to keep it fixed to the xaxis, independent of the y-limits. Setting the actual spine invisible and turning clip_on off makes the LineCollection look like the axis spine.

import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection
import numpy as np

fig, ax = plt.subplots()

colors=["b","r","lightgreen","gold"]
x=[0,.25,.5,.75,1]
y=[0,0,0,0,0]
points = np.array([x, y]).T.reshape(-1, 1, 2)
segments = np.concatenate([points[:-1], points[1:]], axis=1)
lc = LineCollection(segments,colors=colors, linewidth=2,
                               transform=ax.get_xaxis_transform(), clip_on=False )
ax.add_collection(lc)
ax.spines["bottom"].set_visible(False)
ax.set_xticks(x)
plt.show()