Question

In python how to know the methods of a class

Ex: import datetime is a module which has a date class in it..
And print datetime.date.today()

will yield todays date.

How to know all the methods of a class

help(datetime) and dir(datetime) are the only way..?

Answer 1

First solution

Following Björn’s answer and the Dive-into-Python chapter using callable(getattr(classname)):

>>> import datetime
>>> c=datetime.datetime
>>> methodList = [method for method in dir(c) if callable(getattr(c, method))]
>>> methodList
['__add__', '__class__', '__delattr__', '__eq__', '__format__', '__ge__',
 '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', 
 '__ne__', '__new__', '__radd__', '__reduce__', '__reduce_ex__', '__repr__', 
 '__rsub__', '__setattr__', '__sizeof__', '__str__', '__sub__', 
 '__subclasshook__', 'astimezone', 'combine', 'ctime', 'date', 'dst', 
 'fromordinal', 'fromtimestamp', 'isocalendar', 'isoformat', 'isoweekday', 
 'now', 'replace', 'strftime', 'strptime', 'time', 'timetuple', 'timetz', 
 'today', 'toordinal', 'tzname', 'utcfromtimestamp', 'utcnow', 'utcoffset',
 'utctimetuple', 'weekday']

Second solution – after reading Guandalino‘s comment

>>> methodList = [item for item in dir(c) 
                  if type(getattr(c, item))==type(getattr(c,'__new__'))]
>>> methodList
['__new__', '__subclasshook__', 'combine', 'fromordinal', 'fromtimestamp', 
 'now', 'strptime', 'today', 'utcfromtimestamp', 'utcnow']

This technique relies on the fact that the __new__ attribute is always a method (It can be overridden, but every other keyword can).