可以使用创建标签ax.text()
。放置标签的一个不错的技巧是使用一种转换,该转换允许将轴坐标用于x位置,将数据坐标用于y位置。
ax.text(1.02, 4.2e4, "42000", .. , transform=ax.get_yaxis_transform())
完整的代码:
import matplotlib.pyplot as plt
import matplotlib.colors
import numpy as np
fig = plt.figure()
ax = fig.add_subplot(111)
x = [0,1,2,3]
y = np.array([34,40,38,50])*1e3
norm = matplotlib.colors.Normalize(30e3, 60e3)
ax.bar(x,y, color=plt.cm.plasma_r(norm(y)) )
ax.axhline(4.2e4, color="gray")
ax.text(1.02, 4.2e4, "42000", va='center', ha="left", b@R_120_2419@=dict(facecolor="w",alpha=0.5),
transform=ax.get_yaxis_transform())
plt.show()