[FIXED] How do I animate several lines at once on a polar plot with matplotlib?

Issue

I have 35 different radial lines that I am displaying on a polar plot that I would like to animate as their angular dispersion increases. If I just want to animate one line I would do something like this:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

speed = 5.5
weight=0.5
angle=0

fig = plt.figure(figsize=(12, 12))
ax = plt.subplot(111, projection = 'polar')
ax.set_theta_direction(-1)
ax.set_theta_offset(np.pi / 2.0)
line, = ax.plot([0, angle], [0, speed],color='blue',linewidth=3,alpha=weight) 
def animate(i):
    angle=i*(np.pi/180)
    new_datax = [0, angle]
    lines.set_xdata(new_datax)
    return lines,
anim = animation.FuncAnimation(fig, animate, frames=360, interval=20)

And that seems to spin round quite nicely! However if "speed, weight and angles" are arrays not just values how can I animate them all at once without having to do 35 different set_xdata? I know it's not like this!

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

speeds = np.array([5.5,5.5,5.1,5.5,5.6,5.7,5.8,6,6.5,7,7.5,8.5,9.5,11.5,17.5,23,26,29,32,27,22,14.5,9.5,6.3,5.5,6,6.5,7,7.5,8,8.5,9,9.5,10,10])
weights = np.array([1,0.93,0.90,0.86,0.83,0.83,0.83,0.83,0.82,0.80,0.73,0.77,0.72,0.68,0.68,0.70,0.59,0.71,0.71,0.64,0.73,0.77,0.74,0.680.636977,0.59,0.54,0.53,0.51,0.48,0.46,0.40,0.44,0.38,0.36])
angles=np.linspace(0,0,35)*(np.pi/180)

fig = plt.figure(figsize=(12, 12))
ax = plt.subplot(111, projection = 'polar')
ax.set_theta_direction(-1)
ax.set_theta_offset(np.pi / 2.0)
for j in range (35):
    lines, = ax.plot([0, angles[j]], [0, speeds[j]],color='blue',linewidth=3,alpha=weight3[j]) 

def animate(i):
    angles=np.linspace(0,i,35)*(np.pi/180)
    for j in range(35):
        new_datax = [0, angles[j]]
        lines.set_xdata(new_datax)
    return lines,
anim = animation.FuncAnimation(fig, animate, frames=360, interval=20)

But I don't know how else to approach this problem! Any help would be greatly appreciated!

Solution

You need to keep track of all the line objects. Right now you're overwriting the lines object every time. Something like this should work:

lines = []
for j in range(35):
    line, = ax.plot([0, angles[j]], [0, speeds[j]], color='blue', linewidth=3, alpha=weights[j])
    lines.append(line)


def animate(i):
    angles = np.linspace(0, i, 35) * (np.pi / 180)
    for j in range(35):
        new_datax = [0, angles[j]]
        lines[j].set_xdata(new_datax)
    return lines,


anim = animation.FuncAnimation(fig, animate, frames=360, interval=20)

Answered By - falafelocelot