axhspan デモ

水平方向または垂直方向のいずれかで軸にまたがる線または四角形、および任意の方向で軸にまたがる線を作成します。

import numpy as np
import matplotlib.pyplot as plt

t = np.arange(-1, 2, .01)
s = np.sin(2 * np.pi * t)

fig, ax = plt.subplots()

ax.plot(t, s)
# Thick red horizontal line at y=0 that spans the xrange.
ax.axhline(linewidth=8, color='#d62728')
# Horizontal line at y=1 that spans the xrange.
ax.axhline(y=1)
# Vertical line at x=1 that spans the yrange.
ax.axvline(x=1)
# Thick blue vertical line at x=0 that spans the upper quadrant of the yrange.
ax.axvline(x=0, ymin=0.75, linewidth=8, color='#1f77b4')
# Default hline at y=.5 that spans the middle half of the axes.
ax.axhline(y=.5, xmin=0.25, xmax=0.75)
# Infinite black line going through (0, 0) to (1, 1).
ax.axline((0, 0), (1, 1), color='k')
# 50%-gray rectangle spanning the axes' width from y=0.25 to y=0.75.
ax.axhspan(0.25, 0.75, facecolor='0.5')
# Green rectangle spanning the axes' height from x=1.25 to x=1.55.
ax.axvspan(1.25, 1.55, facecolor='#2ca02c')

plt.show()