Class definition parameter vs. Normal class definition

Question

What is the difference between the two? Don't both of these have the same functionality? I don't understand the whole point of the object parameter.

class Car(object): # object parameter
    def foobar():
        print("Hello World!\n")

vs.

class Car(): # No parameter
    def foobar():
        print("Hello World!\n")

The first is a new style class, and the latter is an old style class. See http://stackoverflow.com/questions/54867/old-style-and-new-style-classes-in-python?rq=1 — dustyrockpyle, Jun 27 '14 at 07:12

score 3 · Accepted Answer · answered Jun 27 '14 at 07:11

3

In Python 2, the former is a "new-style class" and the latter is an "old-style class" that only exists for backwards compatibility. You should never use the latter for anything new.

In Python 3, I believe there is no difference at all. You can even leave out the parentheses entirely.

answered Jun 27 '14 at 07:11

Andrew Gorcester

19,595
7
57
73

So is there a technically right way to do it? – user1757703 Jun 27 '14 at 07:23
@user1757703 As you probably want new-style classes, always use `(object)` if you want to stay backward-compatible. – glglgl Jun 27 '14 at 07:40

score 0 · Answer 2 · answered Jun 27 '14 at 07:12

In two words:

# new style
class Car(object):
    pass

A "New Class" is the recommended way to create a class in modern Python.

# classic style
class Car():
    pass

A "Classic Class" or "old-style class" is a class as it existed in Python 2.1 and before. They have been retained for backwards compatibility. This page attempts to list the differences.

Please look at:

Class definition parameter vs. Normal class definition

2 Answers2