用Python绘制动画箭头

Question

我正在尝试在Python中为诸如wind之类的矢量设置动画。我尝试在pylab中使用quiver函数，并与matplotlib中的matplotlib.animation结合使用。但是，结果显示'QuiverKey' object is not subscriptable。我认为这是因为我不完全了解这两个函数或者只是这两个函数不匹配在一起。下面是我的代码，它实际上是来自matplotlib的箭头和动画函数之间的组合。

def update_line(num, data, line):
    line.set_data(data[...,:num])
    return line,

X,Y = np.meshgrid(np.arange(0,2*np.pi,.2),np.arange(0,2*np.pi,.2) )  
U = np.cos(X)
V = np.sin(Y)

fig1 = plt.figure()
Q = quiver( X[::3, ::3], Y[::3, ::3], U[::3, ::3], V[::3, ::3],
        pivot='mid', color='r', units='inches' )
data = quiverkey(Q, 0.5, 0.03, 1, r'$1 \frac{m}{s}$', fontproperties={'weight': 'bold'})
plt.axis([-1, 7, -1, 7])
title('scales with plot width, not view')
l, = plt.plot([], [], 'r-') 
plt.xlabel('x')
plt.ylabel('y')
plt.title('test')
line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l),
interval=50, blit=True)
plt.show() 

Answer 1

这是一个让你入门的例子：

import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation

X, Y = np.mgrid[:2*np.pi:10j,:2*np.pi:5j]
U = np.cos(X)
V = np.sin(Y)

fig, ax = plt.subplots(1,1)
Q = ax.quiver(X, Y, U, V, pivot='mid', color='r', units='inches')

ax.set_xlim(-1, 7)
ax.set_ylim(-1, 7)

def update_quiver(num, Q, X, Y):
    """updates the horizontal and vertical vector components by a
    fixed increment on each frame
    """

    U = np.cos(X + num*0.1)
    V = np.sin(Y + num*0.1)

    Q.set_UVC(U,V)

    return Q,

# you need to set blit=False, or the first set of arrows never gets
# cleared on subsequent frames
anim = animation.FuncAnimation(fig, update_quiver, fargs=(Q, X, Y),
                               interval=50, blit=False)
fig.tight_layout()
plt.show()