嵌套列表转换为单列表

1.递归实现

a = [1,[2,[3],4],5]
def list_more(arg):
    new_list = []
        for i in arg:
            if type(i) is not list:
                new_list.append(i)
        else:
            new_list.extend(list_more(i))
     return new_list

In [65]: list_more(a)
Out[65]: [1, 2, 3, 4, 5]