Why init in python fail

Question

I'm using python2.7 to define a function like this

def foo(*args, **kwargs):
    print 'args = ', args
    print 'kwargs = ', kwargs
    print '---------------------------------------'

and by calling foo(3), the output is as the following:

args =  (3,)
kwargs =  {}

which is desired.

But as for __init__ function in a class in which the parameters are the same form as foo, I can't instantize the class Person by invoking Person(3)

def Person():
    def __init__(self, *args, **kwargs):
        print args
        print kwargs
x = Person(3)

The output is

    x = Person(3)
TypeError: Person() takes no arguments (1 given)

That confused me a lot, have I missed something?

possible duplicate of Accessing variable and functions in object oriented python - python — Martijn Pieters
– Martijn Pieters, Commented Sep 7, 2013 at 6:58

TerryA · Accepted Answer · 2013-09-07 06:43:54Z

6

You probably meant to create a class instead of a function:

class Person():
    def __init__(self, *args, **kwargs):
        print args
        print kwargs

__init__ is for classes :).

answered Sep 7, 2013 at 6:43

TerryA

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4 Comments

speedmancs Over a year ago

So, how can I use *args and **kwargs for the construct function of a class. I'm initially trying to overload the initialization function within a class but python doesn't support that feature. The desired calling is as the following: a = Person(name="xxx") b = Person(age=16)

user2357112 Over a year ago

@speedmancs: You do it exactly the way you had it in your code, except without accidentally using def where you meant class.

speedmancs Over a year ago

Thank you, I've really made this mistake:)

TerryA Over a year ago

@speedmancs Don't worry, everyone makes mistakes every once in a while ;). Also, don't forget to accept the answer :)!

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