多维数组，两种效果

>>> b=[]
>>> a = [[1,2],[3,4],[5,6]]
>>> for i in range(len(a)):
...    b.append(a[i])
...
>>> b
[[1, 2], [3, 4], [5, 6]]
>>>

>>> b=[]
>>>
>>> a = [[1,2],[3,4],[5,6]]
>>> b.append(a)
>>> b
[[[1, 2], [3, 4], [5, 6]]]
>>>

　　

　　https://blog.csdn.net/u013733326/article/details/78096511