You can use numpy.nonzero: http://docs.scipy.org/doc/numpy-1.10.1/reference/generated/numpy.nonzero.html
myList = [0.0 , 0.0, 0.0, 2.0, 2.0]
I = np.nonzero(myList)
#the first index is necessary because the vector is within a tuple
first_non_zero_index = I[0][0]
#3