动画在Matplotlib上不起作用

Question

我正在尝试使形状的动画随着样本大小的增加（从100增加到1000）而呈指数分布。还有一个滑块，用于配置发行版的lambda参数，以及一个用于启动动画的按钮。

我的问题是，即使布局得到渲染，当我按下开始按钮时也没有动画发生。到目前为止，这是我的尝试：

为了简化起见，我在Python笔记本中运行它：

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from matplotlib.widgets import Slider

n0 = 100
n1 = 1000

#Create figure object
fig, ax = plt.subplots(1,1)
plt.subplots_adjust(bottom=0.3)

#Create Sliders for parameters
axlam = plt.axes([0.20, 0.05, 0.20, 0.03], facecolor=axcolor)

slam = Slider(axlam, 'Exp lambda', 0, 5, valinit=1)

#Default distributions
dexp = np.random.exponential(1, n1)

#Updates distributions when sliders are changed
def updateDist(val):
    lam = slam.val
    dexp = np.random.exponential(lam, n1)

slam.on_changed(updateDist)

#updates plot on FuncAnimation call
def update(curr):
    if( curr == (n1-n0) ):
        a.event.source.stop()
    plt.cla()
    bins_exp = np.arange(0,4/slam.val,0.25)
    ax.hist(dexp[:(n0+curr)],bins=bins_exp)
    ax.set_title('Exp n={}'.format(n0+curr))

#Define Start button and function to start animation
goax = plt.axes([0.8, 0.025, 0.1, 0.04])
button = Button(goax, 'Start', color=axcolor, hovercolor='0.975')

a = None
def start(event):
    a = animation.FuncAnimation(fig,update,interval=100)
button.on_clicked(start)

Answer 1

您应该注意函数的名称空间。

考虑

a = 0
def f():
    a = 1
f()
print(a) # will print 0

因此，您需要处理实际对象，而不是它们的某些本地副本。

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from matplotlib.widgets import Slider, Button

n0 = 100
n1 = 1000

#Create figure object
fig, ax = plt.subplots(1,1)
plt.subplots_adjust(bottom=0.3)

#Create Sliders for parameters
axcolor = "skyblue"
axlam = plt.axes([0.20, 0.05, 0.20, 0.03], facecolor=axcolor)

slam = Slider(axlam, 'Exp lambda', 0, 5, valinit=1)

#Default distributions
dexp = [np.random.exponential(1, n1)]

##Updates distributions when sliders are changed
def updateDist(val):
    lam = slam.val
    dexp[0] = np.random.exponential(lam, n1)

slam.on_changed(updateDist)

#updates plot on FuncAnimation call
def update(curr):
    if( curr == (n1-n0) ):
        a.event.source.stop()
    ax.clear()
    bins_exp = np.arange(0,4/slam.val,0.25)
    ax.hist(dexp[0][:(n0+curr)],bins=bins_exp)
    ax.set_title('Exp n={}'.format(n0+curr))
    fig.canvas.draw_idle()

#Define Start button and function to start animation
goax = plt.axes([0.8, 0.025, 0.1, 0.04])
button = Button(goax, 'Start', color=axcolor, hovercolor='0.975')

a = [0]
def start(event):
    a[0] = animation.FuncAnimation(fig,update,interval=100)
button.on_clicked(start)

plt.show()