Numpy 返回数组大小

import numpy as np

a = [[1, 2], [3, 4], [5, 6]]

b = np.array(a)

len(a)  # 3

len(b)  # 3

np.size(a)  # 3

np.size(a, 0)  # 3

np.size(a, 1)  # err

b.size  # 6

np.size(b)  # 6

np.size(b, 0)  # 3

np.size(b, 1)  # 2

np.shape(a)  # (3,)

b.shape  # (3, 2)

np.shape(b)  # (3, 2)

b.dtype  # dtype('int32')

c = [[1, 2], [3, 4], [5, 6, 7]]

d = np.array(c)

len(c)  # 3

len(d)  # 3

np.size(c)  # 3

np.size(c, 0)  # 3

np.size(c, 1)  # err

d.size  # 3

np.size(d)  # 3

np.size(d, 0)  # 3

np.size(d, 1)  # err

np.shape(c)  # (3,)

d.shape  # (3,)

np.shape(d)  # (3,)

d.dtype  # dtype('O')