method overloading in python

Question

I need to call unparameterised method first, but also parameterized first, but it is giving an error.

>>> class A:
...     def first(self):
...             print 'first method'
...     def first(self,f):
...             print 'first met',f
...
>>> a=A()
>>> a.first()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: first() takes exactly 2 arguments (1 given) 

Is it possible to do method overloading in Python like in Java?

Answer 1

Your second first method is overriding the original first method. In Python, it is not possible to create overloaded methods the same way as in Java.

However, you can create methods with optional and/or keyword-based arguments and process those accordingly. Here's an example:

class A:
    def first(self, f=None):
        if f is not None:
            print 'first met', f
        else:
            print 'first method'

Usage:

a = A()
a.first()
a.first('something')