from numpy import *
 
>a=array([[1,2],[3,4],[5,6]]) ###此时a是一个array对象
>a
array([[1,2],[3,4],[5,6]])
>a.flatten()
array([1,2,3,4,5,6]) 

> a=mat([[1,2,3],[4,5,6]])
> a
matrix([[1, 2, 3],
  [4, 5, 6]])<br a.flatten()<br>matrix([[1, 2, 3, 4, 5, 6]])<br> 

> a=[[1,2,3],[4,5,6],['a','b']]
[[1, 2, 3], [4, 5, 6], ['a', 'b']]
> a.flatten()      ###报错
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'list' object has no attribute 'flatten' 

> [y for x in a for y in x]
[1, 2, 3, 4, 5, 6, 'a', 'b']

> a = [[1,3],[2,4],[3,5]]
> a = mat(a)
> y = a.flatten()
> y
matrix([[1, 3, 2, 4, 3, 5]])
> y = a.flatten().A
> y
array([[1, 3, 2, 4, 3, 5]])
> shape(y)
(1, 6)
> shape(y[0])
(6,)
> y = a.flatten().A[0]
> y
array([1, 3, 2, 4, 3, 5])