Python中的 Matplotlib.axes.Axes.quiverkey()

Matplotlib是Python中的一个库，它是 NumPy 库的数值数学扩展。 Axes 类包含大部分图形元素：Axis、Tick、Line2D、Text、Polygon 等，并设置坐标系。 Axes 的实例通过回调属性支持回调。

matplotlib.axes.Axes.quiverkey()函数

matplotlib 库的 axes 模块中的Axes.quiverkey()函数也用于向颤动图添加键。

Syntax: Axes.quiverkey(self, Q, X, Y, U, label, **kw)

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

Q: This parameter is the Quiver instance returned by a call to quiver.
X, Y : These parameter are the x and y coordinates of the location of the key.
U: This parameter is the length of the key.
label: This parameter is a string with the length and units of the key.
angles : This parameter is the angle of the arrows.
color : This parameter is the overrides face and edge colors from Q.
labelpos : This parameter is used to position the label above, below, to the right, to the left of the arrow.
labelsep: This parameter is the distance in inches between the arrow and the label.
labelcolor: This defaults to default Text color.
fontproperties: This parameter is the dictionary with keyword arguments accepted by the FontProperties initializer: family, style, variant, size, weight.

编程需要懂一点英语

下面的示例说明了 matplotlib.axes 中的 matplotlib.axes.Axes.quiverkey()函数：

示例 1：

# Implementation of matplotlib function
import matplotlib.pyplot as plt
import numpy as np
       
X = np.arange(-20, 20, 0.5)
Y = np.arange(-20, 20, 0.5)
U, V = np.meshgrid(X, Y)
   
fig, ax = plt.subplots()
q = ax.quiver(X, Y, U, V)
ax.quiverkey(q, X = 0.5, Y = 0.5, U = 500,
             label ='Quiver key')
   
ax.set_title('matplotlib.axes.Axes.quiverkey() \
Example', fontsize = 14, fontweight ='bold')
plt.show()

输出：

示例 2：

# Implementation of matplotlib function
import matplotlib.pyplot as plt
import numpy as np
       
X, Y = np.meshgrid(np.arange(0, 2 * np.pi, .2), np.arange(0, 2 * np.pi, .2))
U = np.cos(X**2)
V = np.sin(Y**2)
C = U**2 + V**2
   
fig, ax = plt.subplots()
Q = ax.quiver(X, Y, U, V, C, units ='width')
ax.quiverkey(Q, 0.4, 0.9, 1,
             r'val = $Cos(x ^ 2)^2 + Sin(x ^ 2)^2$',
             labelpos ='E',
             coordinates ='figure')
  
ax.set_title('matplotlib.axes.Axes.quiverkey() \
Example\n', fontsize = 14, fontweight ='bold')
plt.show()

输出：