Python里的append和extend
append()用法示例：
>>> mylist = [1,2,0,'abc']
>>> mylist
[1, 2, 0, 'abc']
>>> mylist.append(4)
>>> mylist
[1, 2, 0, 'abc', 4]
>>> mylist.append('haha')
>>> mylist
[1, 2, 0, 'abc', 4, 'haha']
extend()用法示例：
>>> mylist
[1, 2, 0, 'abc', 4, 'haha']
>>> mylist.extend(['lulu'])
>>> mylist
[1, 2, 0, 'abc', 4, 'haha', 'lulu']
>>> mylist.extend([aaa,'lalalala'])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'aaa' is not defined
>>> mylist.extend(['123123','lalalala'])
>>> mylist
[1, 2, 0, 'abc', 4, 'haha', 'lulu', '123123', 'lalalala']
>>> mylist.extend([111111,222])
>>> mylist
[1, 2, 0, 'abc', 4, 'haha', 'lulu', '123123', 'lalalala', 111111, 222]
看到了吗？append()只能在list中添加一个元素；extend()只能添加另外一个list。