Python中flatten用法，有需要的朋友可以参考下。
一、用在数组
>>> a = [[1,3],[2,4],[3,5]]
>>> a = array(a)
>>> a.flatten()
array([1, 3, 2, 4, 3, 5])
二、用在列表
如果直接用flatten函数会出错
>>> a = [[1,3],[2,4],[3,5]]
>>> a.flatten()
Traceback (most recent call last):
File "<pyshell#10>", line 1, in <module>
a.flatten()
AttributeError: 'list' object has no attribute 'flatten'正确的用法
>>> a = [[1,3],[2,4],[3,5],["abc","def"]]
>>> a1 = [y for x in a for y in x]
>>> a1
[1, 3, 2, 4, 3, 5, 'abc', 'def']或者（不理解）
>>> a = [[1,3],[2,4],[3,5],["abc","def"]]
>>> flatten = lambda x: [y for l in x for y in flatten(l)] if type(x) is list else [x]
>>> flatten(a)
[1, 3, 2, 4, 3, 5, 'abc', 'def']
三、用在矩阵
>>> 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])原文网址：Python中flatten用法，有需要的朋友可以参考下。
