How to check whether a method exists in Python?

Question

In the function __getattr__(), if a referred variable is not found then it gives an error. How can I check to see if a variable or method exists as part of an object?

import string import logging  class Dynamo:  def __init__(self,x):   print "In Init def"   self.x=x  def __repr__(self):   print self.x  def __str__(self):   print self.x  def __int__(self):   print "In Init def"  def __getattr__(self, key):     print "In getattr"     if key == 'color':         return 'PapayaWhip'     else:         raise AttributeError   dyn = Dynamo('1') print dyn.color dyn.color = 'LemonChiffon' print dyn.color dyn.__int__() dyn.mymethod() //How to check whether this exist or not 

Answer 1

Check if class has such method?

hasattr(Dynamo, key) and callable(getattr(Dynamo, key)) 

or

hasattr(Dynamo, 'mymethod') and callable(getattr(Dynamo, 'mymethod')) 

You can use self.__class__ instead of Dynamo

Answer 2

It's easier to ask forgiveness than to ask permission.

Don't check to see if a method exists. Don't waste a single line of code on "checking"

try:     dyn.mymethod() # How to check whether this exists or not     # Method exists and was used.   except AttributeError:     # Method does not exist; What now?