AttributeError：“列表”对象没有属性“get_label”

Question

我试着用两个y轴和一个x轴来绘制基本图。为了获得不同曲线的图例信息，我得到了AttributeError。这是我的代码：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2.0*np.pi, 101)
y = np.sin(x)
z = np.sinh(x)

# separate the figure object and axes object from the plotting object
fig, ax1 = plt.subplots()

# Duplicate the axes with a differebt y axis and the same x axis
ax2 = ax1.twinx()  # ax2 and ax1 will have common x axis and different y axis

# plot the curves on axes 1, and 2 and get the curve hadles
curve1 = ax1.plot(x, y, label="sin", color='r')
curve2 = ax2.plot(x, z, label="sinh", color='b')

# Make a curves list to access the parameters in the curves
curves = [curve1, curve2]

# Add legend via axes1 or axex 2 object.
# ax1.legend() will not display the legend of ax2
# ax2.legend() will not display the legend of ax1

ax1.legend(curves, [curve.get_label() for curve in curves])
#ax2.legend(curves, [curve.get_label() for curve in curves]) also valid

# Global figure properties
plt.title("Plot of sine and hyperbolic sine")
plt.show()

我在下面的线上出错了：

ax1.legend(curves, [curve.get_label() for curve in curves])

如果有人知道为什么会发生，请告诉我。

Answer 1

这将解决您的问题，尝试如下：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2.0*np.pi, 101)
y = np.sin(x)
z = np.sinh(x)

# separate the figure object and axes object from the plotting object
fig, ax1 = plt.subplots()

# Duplicate the axes with a differebt y axis and the same x axis
ax2 = ax1.twinx()  # ax2 and ax1 will have common x axis and different y axis

# plot the curves on axes 1, and 2 and get the curve hadles
curve1 = ax1.plot(x, y, label="sin", color='r')
curve2 = ax2.plot(x, z, label="sinh", color='b')

# Make a curves list to access the parameters in the curves
curves = curve1 + curve2

# Add legend via axes1 or axex 2 object.
# ax1.legend() will not display the legend of ax2
# ax2.legend() will not display the legend of ax1
labs = [curve.get_label() for curve in curves]
ax1.legend(curves, labs, loc=0)

#ax1.legend(curves, [curve.get_label() for curve in curves])
#ax2.legend(curves, [curve.get_label() for curve in curves]) also valid

# Global figure properties
plt.title("Plot of sine and hyperbolic sine")
plt.show()

Answer 2

如果您读取拟图文档，您可以看到绘图函数返回一个列表，该列表显然没有方法get_label()。

您想要的可能是在matplotlib的图例文档中描述的内容，它是自动检测您的情节的标签。这意味着您不必存储您的行结果，您的图例调用将从

ax1.legend(curves, [curve.get_label() for curve in curves])

简单地

ax1.legend()

在我看来，阅读文档不仅在大多数情况下解决了您的问题，而且在编程世界中给您提供了一种非常重要的能力，即能够自己解决问题(以及阅读文档)。

干杯