Python中的 matplotlib.pyplot.axhline()

Matplotlib是Python中的一个库，它是 NumPy 库的数值数学扩展。 Pyplot是Matplotlib模块的基于状态的接口，它提供了一个类似 MATLAB 的接口。

matplotlib.pyplot.axhline()函数

matplotlib 库的 pyplot 模块中的axhline()函数用于在轴上添加一条水平线。

Syntax: matplotlib.pyplot.axhline(y=0, xmin=0, xmax=1, **kwargs)

Parameters: This method accept the following parameters that are described below:

• y: This parameter is an optional and it is position in data coordinates of the horizontal line.
• xmin: This parameter is a scalar and optional. Its default value is 0.
• xmax: This parameter is a scalar and optional. Its default value is 1.

Returns: This returns the following:

line : This returns the line created by this function.

下面的示例说明了 matplotlib.pyplot 中的 matplotlib.pyplot.axhline()函数：

示例 #1：

# Implementation of matplotlib.pyplot.annotate() function
  
import numpy as np
import matplotlib.pyplot as plt
  
t = np.linspace(-10, 10, 100)
sig = 1 / t
  
plt.axhline(y = 0, color ="green", linestyle ="--")
plt.axhline(y = 0.5, color ="green", linestyle =":")
plt.axhline(y = 1.0, color ="green", linestyle ="--")
  
plt.axvline(color ="black")
  
plt.plot(t, sig, linewidth = 2, 
         label = r"$\sigma(t) = \frac{1}{x}$")
  
plt.xlim(-10, 10)
plt.xlabel("t")
plt.title("Graph of 1 / x")
plt.legend(fontsize = 14)
  
plt.show()

输出：

示例 #2：

# Implementation of matplotlib.pyplot.annotate() 
# function
  
import numpy as np
import matplotlib.pyplot as plt
  
x = np.linspace(0, 13, 100)
  
plt.rcParams['lines.linewidth'] = 2
plt.figure()
  
plt.plot(x, np.sin(x), label ='Line1', 
         color ='green', linestyle ="--")
  
plt.plot(x, np.sin(x + 0.5), label ='Line2',
         color ='black', linestyle =":")
  
plt.axhline(0, label ='Line3', color ='black')
  
  
plt.title('Axhline() Example')
l = plt.legend(loc ='upper right')
  
# legend between blue and orange 
# line
l.set_zorder(2.5)
  
plt.show()

输出：