import numpy as np

x = np.matrix([[1,2],[3,-4]])
print(np.linalg.norm(x))
print(np.linalg.norm(x, -2))
print(np.linalg.norm(x, -1))
print(np.linalg.norm(x, 1))
print(np.linalg.norm([1,2,0,3,4,0], 0))
print(np.linalg.norm([1,2,0,3,4,0], 2))