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Defining a Class A class in Python can be defined using the class keyword. As per the syntax above, a class is defined using the class keyword followed by the class name and : operator after the class name, which allows you to continue in the next indented line to define class members. The followings are class members.
Defining Class and Declaring Objects A class is defined in C++ using keyword class followed by the name of class. The body of class is defined inside the curly brackets and terminated by a semicolon at the end.
Python is an object oriented programming language. Almost everything in Python is an object, with its properties and methods. A Class is like an object constructor, or a "blueprint" for creating objects.
In this code: class A(object): def __init__(self): self.x = 'Hello' def method_a(self, foo): print self.x + ' ' + foo. ... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidden parameter to the methods defined on an object; Python does not.
While it might not be syntactically incorrect to use the empty parentheses in a class definition, parentheses after a class definition are used to indicate inheritance, e.g:
class A(baseClass):
...
In Python, the preferred syntax for a class declaration without any base classes is simply:
class A:
...
Don't use parentheses unless you are subclassing other classes.
The docs on the matter should give you a better understanding of how to declare and use classes in Python.
The latter is a syntax error on older versions of Python. In Python 2.x you should derive from object whenever possible though, since several useful features are only available with new-style classes (deriving from object is optional in Python 3.x, since new-style classes are the default there).
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