004_006 Python 展开嵌套序列 序列的子序列进行展开

代码如下：

#encoding=utf-8

print '中国'

#展开嵌套序列 序列的子序列进行展开

print '----递归'
def list_or_tuple(x):
    return isinstance(x,(list,tuple))

def flatten(sequence, to_expand=list_or_tuple):
    for item in sequence:
        if to_expand(item):
            for subitem in flatten(item,to_expand):
                yield subitem
        else:
            yield item
            

lista=[[1,2,[3,4,[5,6]]],7,8,(9,10,(11,12))]

for idx,item in enumerate(flatten(lista)):
    print idx,item
    
print '----非递归 链表'

def flatten2(sequence, to_expand=list_or_tuple):
    iterators = [ iter(sequence) ]
    while iterators:       
        for item in iterators[-1]:
            if to_expand(item):                
                iterators.append(iter(item))
                break
            else:
                yield item
        else:            
            iterators.pop( )


for idx,item in enumerate(flatten2(lista)):
    print idx,item
    

打印结果如下：

中国
----递归
0 1
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12
----非递归 链表
0 1
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12