使用交互式鼠标时列表不附加值

Question

我在同一张图中绘制了三组数据。我正在尝试使用 mpldatacursor 库，以便我可以单击这些点并将值存储到与数据集相对应的单独列表中。该程序似乎在运行，但这些值并未存储到我定义的列表（zradius、zangle 和 zamp）中。在程序中，我明确声明要附加单击的值，但这似乎失败了，因为没有存储任何值。我不确定我是否遗漏了什么或者我附加它们的方式在这种情况下不起作用？关于为什么列表是空的有什么建议吗？

fig1, ax = plt.subplots()
fig1 = plt.figure(figsize= (10,10))
radius  = np.sqrt(actual_x**2 + actual_y**2)
angle = np.arctan2(actual_y,actual_x)
angle = angle/0.01745
amplitudez = amp0/10.
#plt.scatter(actual_z,actual_x, color = 'r', label = 'Experiment Trajectory(x_z)',marker = 
             '*',s = 20)

for i in range(len(actual_x)):
    ax.scatter([actual_z],[radius], color = 'black', 
               label='ID: Z: {:.2f},Radius: {:.2f}'.format(actual_z[i],radius[i]),marker = 
               '*',s = 20)
    ax.scatter([actual_z],[angle], color = 'green', 
               label='ID: Z: {:.2f},Angle: {:.2f}'.format(actual_z[i],angle[i]),marker = '*',s 
               = 20)
    ax.scatter([actual_z],[amplitudez], color = 'brown', 
               label='ID: Z: {:.2f},AmpZ: {:.2f}'.format(actual_z[i],amplitudez[i]),marker = 
               'x',s = 20)

ax.set_title('Experimental Data event:')
ax.set_xlabel('Z values')
ax.set_ylabel('Y/X values')
ax.set_xlim(100,700)
# # plt.ylim(-150,150)
#ax.legend()
ax.grid()
#print(' event number:',selected_event)
#print('Experimental Trajectory:','Theta:', exp_theta, 'Phi:', exp_phi, 'Energy:', exp_energy 
      )
datacursor(formatter='{label}'.format, bbox=dict(fc='yellow', alpha =10.0, snap =True))
zradius, zangle, zamp = [], [], []

def onclick(event):
    global iz, iradius, iangle, iamplitudez
    iz, iradius, iangle, iamplitudez = event.zdata, event.rdata, event.adata, event.ampdata
#     print ('x = %d, y = %d'%(
#         ix, iy))

    global zradius, zangle, zamp
    zradius.append((iz, iradius))
    zangle.append((iz, iangle))
    zamp.append((iz, iamplitudez))

    if len(zradius) == len(actual_x):
        fig.canvas.mpl_disconnect(cid)

    return zradius, zangle, zamp
cid = fig.canvas.mpl_connect('button_press_event', onclick)

输出显示：

In[7]: zradius
Out[7]: []