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 "
    
     ", line 1, in 
     
          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。