about the args of matplotlib.animation.FuncAnimation
animation, matplotlib, python
Solution
It looks like the documentation is off, or at least unclear here: the function has an intrinsic first argument, the frame number. So you can simply define it as `def animate(*args)` or `def animate(framenumber, *args)`, or even `def animate(framenumber, *args, **kwargs)`.
See also this example.
Note that you'll run into other problems after that:
`i` and `x` within `animate` should be declared `global`. Or better, pass them as arguments through the `fargs` keyword in `FuncAnimation`.
`x = x[1:] + [i]` doesn't work the way you think it does. Numpy arrays work differently than lists: it would add `[i]` to every element of `x[1:]` and assign that to `x`, thus making `x` one element shorter. One possible correct way would be `x[:-1] = x[1:]; x[-1] = i`.
Problem
``` import numpy as np import matplotlib.pyplot as plt import matplotlib.animation as animation fig = plt.figure() ax = fig.add_subplot(111) x = np.arange(0, 2*np.pi, 0.01) # x-array i=1 line, = ax.plot(x, np.sin(x)) def animate(): i= i+2 x=x[1:] + [i] line.set_ydata(np.sin(x)) # update the data return line, #Init only required for blitting to give a clean slate. def init(): line.set_ydata(np.ma.array(x, mask=True)) return line, ani = animation.FuncAnimation(fig, animate, init_func=init, interval=25, blit=True) plt.show() ``` I get error like this:animate() takes no arguments (1 given)..so confused. i don't even give an arg to the callback func. Was there something that i missed? thanks.