python 类成员函数的参数问题

Question

今天遇到一个没见过的代码：

class Iface:
  def ping(self, ):                                                                                                                                                                      
    pass                                                                                                                                                                                 
  def say(self, msg):                                                                                                                                                                    
    """
    Parameters:                                                                                                                                                                          
     - msg                                                                                                                                                                               
    """
    pass

这里ping()的参数是以逗号结尾，是指参数为有一个元素的元组吗？

Answer 1

其中函数定义部分：

funcdef: 'def' NAME parameters ':' suite
parameters: '(' [varargslist] ')'varargslist: ((fpdef ['=' test] ',')*
              ('*' NAME [',' '**' NAME] | '**' NAME) |
              fpdef ['=' test] (',' fpdef ['=' test])* [','])

Answer 2

Python的参数本来就是用tuple来实现的。关于这一点，你可以去看看怎么写一个Python C扩展，你就会有很深的了解了，其中PyArg_ParseTuple是一个最常用的API。