如何将对象传递给单独的函数-Python

debugcn 发表于 Dev

强子

我的目标是使用下面的df制作散点图的动画。我正在尝试将plotandgroups函数传递给该animate函数。我试图从每个函数返回值，然后将它们传递给后续函数，但NameError由于没有注册这些值，因此我得到了。

如果我删除plot和groups函数，并从全局工作区传递对象以进行动画处理，则脚本可以工作，但是我必须一直将它们写出来。而不是将其置于单独的功能中。

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
import matplotlib as mpl
from matplotlib import animation

df1 = pd.DataFrame({
    'Time' : [1,1,1,2,2,2,3,3,3],        
    'GroupA_X' : [3, 4, 5, 2, 5, 6, 1, 6, 7], 
    'GroupA_Y' : [2, 4, 5, 2, 5, 5, 2, 6, 5],            
    'GroupB_X' : [2, 5, 3, 2, 4, 2, 2, 3, 1],   
    'GroupB_Y' : [2, 4, 3, 3, 3, 4, 4, 2, 5],                 
        })

def plot():

    fig, ax = plt.subplots()
    ax.grid(False)

    xy = 0,0
    Oval = mpl.patches.Ellipse(xy, 160, 130, lw = 2, edgecolor = 'black', color = 'blue', alpha = 0.2)
    ax.add_patch(Oval)

    return fig, ax

def groups():

    plot()

    Group_A = df1[['Time','GroupA_X','GroupA_Y']]
    Group_B = df1[['Time','GroupB_X','GroupB_Y']]

    GA_X = np.array(Group_A.groupby(['Time'])['GroupA_X'].apply(list))
    GA_Y = np.array(Group_A.groupby(['Time'])['GroupA_Y'].apply(list))

    GB_X = np.array(Group_B.groupby(['Time'])['GroupB_X'].apply(list))
    GB_Y = np.array(Group_B.groupby(['Time'])['GroupB_Y'].apply(list))

    GA = ax.scatter(GA_X[0], GA_Y[0], c = ['blue'], marker = 'o', s = 10, edgecolor = 'black')
    GB = ax.scatter(GB_X[0], GB_Y[0], c = ['brown'], marker = 'o', s = 10, edgecolor = 'black')

    return GA, GB

def animate(i) :

    plot()
    groups()

    GA.set_offsets(np.c_[GA_X[0+i], GA_Y[0+i]])
    GB.set_offsets(np.c_[GB_X[0+i], GB_Y[0+i]])

plot()
groups()

ani = animation.FuncAnimation(fig, animate, np.arange(0,3), interval = 1000, blit = False)

错误输出：

GA = ax.scatter(GA_X[0], GA_Y[0], c = ['blue'], marker = 'o', s = 10, edgecolor = 'black')
NameError: name 'ax' is not defined

安迪（Andy L.）

动画在global上绘制/重复figure，因此您需要subplots在global范围内创建。如果您定义subplots内部plot函数，则每次调用plot都会创建一个新的subplots

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
import matplotlib as mpl
from matplotlib import animation

df1 = pd.DataFrame({
    'Time' : [1,1,1,2,2,2,3,3,3],        
    'GroupA_X' : [3, 4, 5, 2, 5, 16, 21, 36, 47], 
    'GroupA_Y' : [2, 4, 5, 2, 5, 15, 22, 36, 45],            
    'GroupB_X' : [2, 5, 3, 2, 4, 12, 22, 33, 41],   
    'GroupB_Y' : [2, 4, 3, 3, 3, 14, 24, 32, 45],                 
        })

fig, ax = plt.subplots()

def plot():

#     fig, ax = plt.subplots() #declared in global scope
    ax.grid(False)

    xy = 0,0
    Oval = mpl.patches.Ellipse(xy, 160, 130, lw = 2, edgecolor = 'black', color = 'blue', alpha = 0.2)
    ax.add_patch(Oval)

#     return fig, ax #no need return since `fig, ax` are in global scope

def groups():

#   plot() #no need since this function use nothing from `plot`

    Group_A = df1[['Time','GroupA_X','GroupA_Y']]
    Group_B = df1[['Time','GroupB_X','GroupB_Y']]

    GA_X = np.array(Group_A.groupby(['Time'])['GroupA_X'].apply(list))
    GA_Y = np.array(Group_A.groupby(['Time'])['GroupA_Y'].apply(list))

    GB_X = np.array(Group_B.groupby(['Time'])['GroupB_X'].apply(list))
    GB_Y = np.array(Group_B.groupby(['Time'])['GroupB_Y'].apply(list))

    GA = ax.scatter(GA_X[0], GA_Y[0], c = ['blue'], marker = 'o', s = 10, edgecolor = 'black')
    GB = ax.scatter(GB_X[0], GB_Y[0], c = ['brown'], marker = 'o', s = 10, edgecolor = 'black')

    return GA, GB, GA_X, GA_Y, GB_X, GB_Y

def animate(i) :

#     plot()
    GA, GB, GA_X, GA_Y, GB_X, GB_Y = groups()

    GA.set_offsets(np.c_[GA_X[0+i], GA_Y[0+i]])
    GB.set_offsets(np.c_[GB_X[0+i], GB_Y[0+i]])

plot() 
# groups()

ani = animation.FuncAnimation(fig, animate, np.arange(0,3), interval = 1000, blit = False)

注意：我更改了值，df1以使每个动画之间的值都更清晰。修复以上工作的代码。我测试了但是，我不知道它是否有效。我基本上只是修复您的代码以使其运行。

您说如果在全局范围内声明所有内容，动画运行就很好。因此，我假设您的系统已经ffmpeg安装并且您的代码能够调用/查找ffmpeg.exe以显示重新定义/循环动画

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