生成重复更新图（FuncAnimation - Matplotlib）

Question

我正在尝试编写一个代码，该代码将生成一个被反复更新并具有双轴（2 个 y 轴，共享相同的 x 轴）的图形。

当我不将它与 FuncAnimation 结合使用时，该代码运行良好，但是当我尝试这样做时，我得到一个空图。


def animate(i):
    data=prices(a,b,c)    #function that gives a DataFrame with 2 columns and index
    plt.cla()   
    fig=plt.figure()
    ax = fig.add_subplot(111)
    ax.plot(data.index, data.value1)
    ax2 = ax.twinx()
    ax2.plot(data.index, data.value2)
    plt.gcf().autofmt_xdate()     
    plt.tight_layout()  

call = FuncAnimation(plt.gcf(), animate, 1000)  
plt.tight_layout()
plt.show
'''


I believe the error is in "call". Unfortunately, I don't know FuncAnimation so well.

Answer 1

您可以尝试这样的操作：

import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation
import pandas as pd
from datetime import datetime, timedelta

def getPrices(i):
    return pd.DataFrame(index=[datetime.now() + timedelta(hours=i) for i in range(10)], data={'value1':range(10), 'value2':[(x + i) % 5 for x in range(10)]})

def doAnimation():
    fig=plt.figure()
    ax = fig.add_subplot(111)

    def animate(i):
        #data=prices(a,b,c)    #function that gives a DataFrame with 2 columns and index
        data = getPrices(i)

        plt.cla()
        ax.plot(data.index, data.value1)
        ax2 = ax.twinx()
        ax2.plot(data.index, data.value2)
        plt.gcf().autofmt_xdate()     
        plt.tight_layout()  
        return ax, ax2

    call = FuncAnimation(plt.gcf(), animate, 1000)  
    plt.show()

doAnimation()

更新:

虽然这在我的环境中有效，但评论中的 OP 表示它不起作用并引发以下警告：

UserWarning: Animation was deleted without rendering anything. This is most likely not intended. To prevent deletion, assign the Animation to a variable, e.g. anim, that exists until you have outputted the Animation using plt.show() or anim.save()

由于 plt.show() 在调用 FuncAnimation() 之后立即被调用，这令人费解，但以下内容可能有助于确保 Animation 不会被过早删除：

import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation
import pandas as pd
from datetime import datetime, timedelta

def getPrices(i):
    return pd.DataFrame(index=[datetime.now() + timedelta(hours=i) for i in range(10)], data={'value1':range(10), 'value2':[(x + i) % 5 for x in range(10)]})

def doAnimation():
    fig=plt.figure()
    ax = fig.add_subplot(111)

    def animate(i):
        #data=prices(a,b,c)    #function that gives a DataFrame with 2 columns and index
        data = getPrices(i)

        plt.cla()
        ax.plot(data.index, data.value1)
        ax2 = ax.twinx()
        ax2.plot(data.index, data.value2)
        plt.gcf().autofmt_xdate()     
        plt.tight_layout()  
        return ax, ax2

    call = FuncAnimation(plt.gcf(), animate, 1000)  
    return call

callSave = doAnimation()
plt.show()

生成重复更新图（FuncAnimation - Matplotlib）

Generating repeatedly updating graph (FuncAnimation - Matplotlib)

python

animation

matplotlib

jupyter-notebook