python 中的 Matplotlib 非对称误差条绘图

Question

尝试绘制范围从负值到正值的不对称误差条时遇到错误。我修改了文档中的示例：

import numpy as np
import matplotlib.pyplot as plt

# example data
x = np.arange(0, 4, 1)
y = -0.2* x


# example error bar values that vary with x-position
error = 0.1 + 0.2 * x

# error bar values w/ different -/+ errors that
# also vary with the x-position
lower_error = -1 * error
upper_error = 4* error
asymmetric_error = [lower_error, upper_error]

plt.errorbar(x, y, yerr=asymmetric_error, fmt='.', ecolor = 'red')
plt.show()

给出了以下情节：

但对于不对称误差具有以下值：

array([-0.1, -0.3, -0.5, -0.7]), array([0.4, 1.2, 2. , 2.8])]

这似乎遵循文档，所以我不确定是什么原因造成的。

Answer 1

较低误差前面不需要负数。

import numpy as np
import matplotlib.pyplot as plt

# example data
x = np.arange(0, 4, 1)
y = -0.2* x


# example error bar values that vary with x-position
error = 0.1 + 0.2 * x

# error bar values w/ different -/+ errors that
# also vary with the x-position
lower_error =  error
upper_error =  4*error
asymmetric_error = np.array(list(zip(lower_error, upper_error))).T

plt.errorbar(x, y, yerr=asymmetric_error, fmt='.', ecolor = 'red')
plt.show()

输出：