python的matplotlib如何给多个子图只添加一个图例

1 方法1

import matplotlib.pyplot as plt

fig = plt.figure()
axes = fig.subplots(nrows=2, ncols=2)

axess = []
for ax in fig.axes:
    axess.append(ax)
    
axess[0].plot([0, 10], [0, 10], label='linear')
axess[1].plot([0, 10], [0, 10], label='linear')
axess[2].plot([0, 10], [0, 10], label='linear')
axess[3].plot([0, 10], [0, 10], label='linear')

lines, labels = fig.axes[-1].get_legend_handles_labels()

fig.legend(lines, labels, loc='upper center')
plt.show()

2 方法2

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(-1, 1, 1000)
y1 = x
y2 = 0.1 * x ** 2
y3 = x ** 3
y4 = x ** 4
y5 = x ** 5

fig, grid = plt.subplots(nrows=2, ncols=2)
# fig.subplots_adjust(wspace=0, hspace=0)
ax1 = plt.subplot(221)
ax1.plot(x, y1, label='1')
ax1.plot(x, y2, label='2')
ax1.plot(x, y3, label='3')
ax2 = plt.subplot(222)
ax2.plot(x, y4, label='4')
ax2.plot(x, y5, label='5')
ax2.plot(x, y1, label='1')

ax1.legend(bbox_to_anchor=(0., 1.02, 1., .102), loc=4, ncol=5, borderaxespad=0.)
plt.show()