IndexError: too many indices for array: array is 0-dimensional, but 1 were indexed

for i in range(1,1000):
    xplot[i]=r[0]
    yplot[i]=r[1]
    accel=fa*norm(v)*v
    accel[1]=accel[1]-g
    r=r+h*v
    v=v+h*accel

and ended up like this

---> 21     xplot[i]=r[0]
IndexError: too many indices for array: array is 0-dimensional, but 1 were indexed

how i fix this? help