import numpy as np
x=np.array([5,5])
y=np.array([2,2])

乘法

np.multiply(x,y)

array([10, 10])

np.dot(x,y)#内积

20

x.shape

(2,)

y.shape

(2,)

x.shape=2,1
x

array([[5],
       [5]])

np.dot(x,y)#维度不一样

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-8-6849a5f7ad6c> in <module>()
----> 1np.dot(x,y)

ValueError: shapes (2,1) and (2,) not aligned: 1 (dim 1) != 2 (dim 0)

y.shape=1,2
y

array([[2, 2]])

x

array([[5],
       [5]])

print(x.shape)
print(y.shape)

(2, 1)
(1, 2)

np.dot(x,y)

array([[10, 10],
       [10, 10]])

np.dot(y,x)

array([[20]])

x=np.array([1,1,1])
y=np.array([[1,2,3],[4,5,6]])
print(x*y)#自动加维数转换

[[1 2 3]
 [4 5 6]]

x=np.array([1,1,1])
y=np.array([1,1,1])
x==y#必须维度一样，逐一进行比较

array([ True,  True,  True])

np.logical_and(x,y)#逻辑与操作

array([ True,  True,  True])

np.logical_or(x,y)#或

array([ True,  True,  True])

np.logical_not(x,y)#非

array([0, 0, 0])