In Python 2.x there are two styles of classes depending on the presence or absence of a built-in type as a base-class −‘Old style’ or "Classic" style classes: they have no built-in type as a base class −>>> class OldFoo:      # no base class ...     pass >>> OldFoo.__bases__ ()"New" style classes: they have a built-in type as a base class meaning that, directly or indirectly, they have object as a base class −>>> class NewFoo(object):           # directly inherit from object ...    pass >>> NewFoo.__bases__ (, )In Python 3.x however, only ... Read More

Metaprogramming in python is defined as the ability of a program to influence itself. It is achieved by using metaclass in python. Metaclasses in Python Metaclasses are an OOP concept present in all python code by default. Python provides the functionality to create custom metaclasses by using the keyword type. Type is a metaclass whose instances are classes. Any class created in python is an instance of type metaclass. The type() function can create classes dynamically as calling type() creates a new instance of type metaclass. Syntax Syntax to create a class using type() is given below − class ... Read More

Python variable name may begin with a single underscore. It functions as a convention to indicate that the variable name is now a private variable. It should be viewed as an implementation detail that could change at any time. Programmers can assume that variables marked with a single underscore are reserved for internal usage. Single underscores are advised for semi-private variables, and double underscores are advised for fully private variables. To paraphrase PEP-8; single leading underscore: a poor signal of "internal use." For instance, from M import * excludes objects with names that begin with an underscore. Syntax The syntax ... Read More

When a double underscore is added as prefix to python variables the name mangling process is applied to a specific identifier(__var) In order to avoid naming conflicts with the subclasses, name mangling includes rewriting the attribute name. Example Following is the program to explain the double underscore in Python − class Python: def __init__(self): self.car = 5 self._buzz = 9 self.__fee = 2 d = Python() print(dir(d)) Output Following is an output of the above code − ['_Python__fee', ... Read More

Data hidingIn Python, we use double underscore before the attributes name to make them inaccessible/private or to hide them.The following code shows how the variable __hiddenVar is hidden.Exampleclass MyClass:     __hiddenVar = 0     def add(self, increment):        self.__hiddenVar += increment        print (self.__hiddenVar) myObject = MyClass() myObject.add(3) myObject.add (8) print (myObject.__hiddenVar)Output 3 Traceback (most recent call last): 11   File "C:/Users/TutorialsPoint1/~_1.py", line 12, in     print (myObject.__hiddenVar) AttributeError: MyClass instance has no attribute '__hiddenVar'In the above program, we tried to access hidden variable outside the class using object and it threw an ... Read More

The cmp() functionThe cmp(x, y) function compares the values of two arguments x and y −cmp(x, y)The return value is −A negative number if x is less than y.Zero if x is equal to y.A positive number if x is greater than y.The built-in cmp() function will typically return only the values -1, 0, or 1. However, there are other places that expect functions with the same calling sequence, and those functions may return other values. It is best to observe only the sign of the result.>>> cmp(2, 8) -1 >>> cmp(6, 6) 0 >>> cmp(4, 1) 1 >>> cmp('stackexchange', ... Read More

In Python, the __str__() method is used to compute the informal or human readable string representation of an object. This method is called by the built-in print(), string and format() functions. This method is called by the implementation of the default __format__() method and the built-in function print(). This method returns the string object. In a class, if the __str__() method is not defined, Python will fall back to using the __repr__() method. If neither of these dunder methods is defined, the class will return the default string representation of the object Example Here, we have created a class named ... Read More

In Python, the __repr__() method is a built-in function used to compute the official string representation of an object. It is used in debugging and logging purposes as it provides a detailed and clear representation of an object. This method is also known as dunder method as it begins with a double underscore in the beginning and at the end. In a class, if __str__() method and the __repr__() method is defined ,then the __str__() method is executed. Example Here, we have created a class named Methods and defined the __repr__() method. When we execute the code, the output ... Read More

Python programmers often need to delete directories for tasks like cleaning up temporary files. Deleting directories isn't as simple as deleting files and requires careful handling. This article explores effective methods for deleting Python directories. We'll provide step-by-step explanations and code examples, covering error handling, read-only files, and recursive removal of subdirectories. Using shutil.rmtree() for Recursive Deletion The shutil module provides the rmtree() function, which recursively deletes a directory and all its contents. This is the simplest method for deleting a directory and all its contents. Example The following code defines a function called delete_directory_with_shutil. This function takes the path ... Read More

In Python, the__init__() method is a special method within a class that gets automatically called when an object is created. It is used to initialize the attributes of the object. It is also known as a constructor. The self is always the first argument to the __init__() method that refers to the instance of the class being created, allowing access to its attributes and methods. Lets try to understand the __init__() method with an example - class Employee: def __init__(self): self.name=input("Enter employee name:") self.id=int(input("Enter id:")) ... Read More