Animating 2 lines on the same plot

Question

I am trying to animate two lines on the same plot. After searching around, I came across this post that seems to be getting me on the right track. When I run this code, the stagnant graph shows with no animation, giving me an error AttributeError: 'AxesSubplot' object has no attribute 'set_data'. I looked up set_data and it says it 'accepts: 2D array (rows are x, y) or two 1D arrays'. Is the animation not working since I'm assigning line1 and line2 to plots and not 2D arrays? I would appreciate any help with getting these lines to animate on my plot, I've tried and tried to no avail. Thanks!

fig, ax = plt.subplots(figsize=(16,8))

#Plot Lines
line1 = sns.lineplot('game_seconds_remaining', 'away_wp', data=game, color='#4F2683',linewidth=2)
line2 = sns.lineplot('game_seconds_remaining', 'home_wp', data=game, color='#869397',linewidth=2)
#Add Fill
ax.fill_between(game['game_seconds_remaining'], 0.5, game['away_wp'], where=game['away_wp']>.5, color = '#4F2683',alpha=0.3)
ax.fill_between(game['game_seconds_remaining'], 0.5, game['home_wp'], where=game['home_wp']>.5, color = '#869397',alpha=0.3)


#Plot Aesthetics - Can Ignore
plt.ylabel('Win Probability %', fontsize=16)
plt.xlabel('', fontsize=16)
plt.axvline(x=900, color='white', alpha=0.7)
plt.axvline(x=1800, color='white', alpha=0.7)
plt.axvline(x=2700, color='white', alpha=0.7)
plt.axhline(y=.50, color='white', alpha=0.7)
plt.suptitle('Minnesota Vikings @ Dallas Cowboys', fontsize=20, style='italic',weight='bold')
plt.title('Min 28, DAL 24 - Week 10 ', fontsize=16, style = 'italic',weight='semibold')


#Labels (And variable assignment for animation below)
x = ax.set_xticks(np.arange(0, 3601,900))
y1 = game['away_wp']
y2 = game['home_wp']
plt.gca().invert_xaxis()
x_ticks_labels = ['End','End Q3','Half','End Q1','Kickoff']
ax.set_xticklabels(x_ticks_labels, fontsize=12)


#Animation - Not working
def update(num, x, y1, y2, line1, line2):
    line1.set_data(x[:num], y1[:num])
    line2.set_data(x[:num], y2[:num])
    return [line1,line2]

ani = animation.FuncAnimation(fig, update, len(x), fargs=[x, y1, y2, line1, line2],
                  interval=295, blit=False)

Answer 1

Tested in python 3.11.2, pandas 2.0.0, matplotlib 3.7.1, seaborn 0.12.2

it seems sns gives AxesSublot and you have to get line(s) for this Axes

ax1 = sns.lineplot(...)
ax2 = sns.lineplot(...)

line1 = ax1.lines[0]
line2 = ax2.lines[1]

Or (because both lines are on the same Axes)

sns.lineplot(x=x, y='away_wp', data=game)
sns.lineplot(x=x, y='home_wp', data=game)

ax = plt.gca()

line1 = ax.lines[0]
line2 = ax.lines[1]

---

EDIT:

For Google Colab it needs

from matplotlib import rc
rc('animation', html='jshtml')

# code without `plt.show()`

ani   # display it

Source: Embedding Matplotlib Animations in Python (google colab notebook)

---

Minimal working code with random data

import random
import seaborn as sns
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib import animation
from matplotlib import rc
rc('animation', html='jshtml')

game = pd.DataFrame({
    'away_wp': [random.randint(-10,10) for _ in range(100)],
    'home_wp': [random.randint(-10,10) for _ in range(100)],
    'game_seconds_remaining': list(range(100)),
})

x = range(len(game))
y1 = game['away_wp']
y2 = game['home_wp']

fig = plt.gcf()
ax = plt.gca()

sns.lineplot(x='game_seconds_remaining', y='away_wp', data=game)
sns.lineplot(x='game_seconds_remaining', y='home_wp', data=game)

line1 = ax.lines[0]
line2 = ax.lines[1]

ax.fill_between(game['game_seconds_remaining'], 0.5, game['away_wp'], where=game['away_wp']>.5, color = '#4F2683',alpha=0.3)
ax.fill_between(game['game_seconds_remaining'], 0.5, game['home_wp'], where=game['home_wp']>.5, color = '#869397',alpha=0.3)
#print(ax.collections)

def update(num, x, y1, y2, line1, line2):
    line1.set_data(x[:num], y1[:num])
    line2.set_data(x[:num], y2[:num])

    ax.clear()
    ax.fill_between(game['game_seconds_remaining'][:num], 0.5, game['away_wp'][:num], where=game['away_wp'][:num]>.5, color = '#4F2683',alpha=0.3)
    ax.fill_between(game['game_seconds_remaining'][:num], 0.5, game['home_wp'][:num], where=game['home_wp'][:num]>.5, color = '#869397',alpha=0.3)

    return line1,line2

ani = animation.FuncAnimation(fig, update, len(x), fargs=[x, y1, y2, line1, line2], interval=295, blit=False)

#plt.show()

ani   # display it

---

EDIT:

The same without seaborn but only plt.plot().

At start I create empty line line1, = plt.plot([], [])

import random
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib import animation
from matplotlib import rc
rc('animation', html='jshtml')

game = pd.DataFrame({
    'away_wp': [random.randint(-10,10) for _ in range(100)],
    'home_wp': [random.randint(-10,10) for _ in range(100)],
    'game_seconds_remaining': list(range(100)),
})

x = range(len(game))
y1 = game['away_wp']
y2 = game['home_wp']

fig = plt.gcf()
ax = plt.gca()

# empty lines at start
line1, = plt.plot([], [])
line2, = plt.plot([], [])

# doesn't draw fill_between at start

# set limits 
ax.set_xlim(0, 100)
ax.set_ylim(-10, 10)

def update(num, x, y1, y2, line1, line2):
    line1.set_data(x[:num], y1[:num])
    line2.set_data(x[:num], y2[:num])
    # autoscale 
    #ax.relim()
    #ax.autoscale_view()

    ax.clear()
    ax.fill_between(game['game_seconds_remaining'][:num], 0.5, game['away_wp'][:num], where=game['away_wp'][:num]>.5, color = '#4F2683',alpha=0.3)
    ax.fill_between(game['game_seconds_remaining'][:num], 0.5, game['home_wp'][:num], where=game['home_wp'][:num]>.5, color = '#869397',alpha=0.3)
    
    return line1,line2

ani = animation.FuncAnimation(fig, update, len(x), fargs=[x, y1, y2, line1, line2], interval=295, blit=False)

#plt.show()

ani