numpy基础知识(二)

数组转置和轴对换

In [4]: arr = np.random.randn(3,2)

In [5]: arr.T
Out[5]: 
array([[-1.61958612,  0.51404498,  1.27702971],
       [-1.49568441, -0.62306175,  0.27173435]])

In [6]: np.dot(arr.T,arr)
Out[6]: 
array([[4.5181063 , 2.44912079],
       [2.44912079, 2.69911737]])
In [4]: arr = np.random.randn