Questions and Answers
What is the primary purpose of encapsulation in Object-Oriented Programming?
Which statement correctly defines inheritance in Object-Oriented Programming?
How does polymorphism enhance Object-Oriented Programming?
What best describes the concept of abstraction in Object-Oriented Programming?
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Which of the following is an example of an association relationship in Object-Oriented Programming?
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In the context of classes and objects, what does a class represent?
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What characterizes an object in Object-Oriented Programming?
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What is a primary benefit of using inheritance in programming?
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What does OOP primarily promote in software development?
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What keyword is used to define a class in Python?
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Which method is automatically called when an object of a class is created in Python?
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Which principle of OOP allows classes to inherit attributes and methods from other classes?
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What does the term 'polymorphism' refer to in Python OOP?
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In Python, how are private variables conventionally indicated?
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What is a primary advantage of using abstraction in OOP?
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Which of the following can be considered an object in the context of OOP?
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What is an example of a method defined within a class in the provided example?
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What is the purpose of the superclass in inheritance?
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What is the purpose of the doc attribute in a Python function?
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In the context of object-oriented programming, what is the role of a derived class?
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Which statement is correct regarding encapsulation?
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What does polymorphism allow in object-oriented programming?
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What is a characteristic feature of object-oriented programming compared to procedural programming?
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Why is data abstraction important in programming?
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Which of the following is an example of an object-oriented programming language?
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What is the initial purpose of defining a class in Python?
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Which statement correctly describes the difference between object-oriented and procedural programming?
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What does the 'car' class's display method do in the provided example?
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What keyword is used to create a class in Python?
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What is the primary purpose of the init() function in a class?
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What will be the output of the following code: p1 = Person('John', 36); print(p1.age)?
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When you pass an object to a function, what are you actually passing?
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What will happen if you try to modify an immutable object, like an integer, inside a function?
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How are object attributes accessed within a function?
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What will the following function return: def is_adult(person): return person.age >= 18?
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If a function modifies the age of a Person object, what impact does it have outside the function?
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What is the result of attempting to print the name of a Person object after it has been created with p1 = Person('Alice', 30)?
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Which of the following is true about passing mutable and immutable objects to functions?
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What will the output be if the function modify_string is called with the string 'Hello'?
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Which attribute provides the name of the class in Python?
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What does a function return if there is no return statement executed?
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What will be the output of the following code?
def get_coordinates(): return 10, 20
x, y = get_coordinates() print(x, y)
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What is the purpose of the doc attribute in a class?
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When returning a custom object from a function, what is returned?
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If a function returns multiple values, how are those values typically retrieved?
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Which of the following can be returned by a function in Python?
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What is the output of print(MyClass.module) if MyClass is defined in the main module?
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Which class attribute contains a dictionary of the class's namespace?
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What happens when there is an attempt to print the private member '__privateCount' from the instance of the class?
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How can you correctly access the private member '__privateCounter' from an instance of the class?
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Which of the following is a disadvantage of data hiding?
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What is one advantage of using data hiding in object-oriented programming?
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Which statement best reflects a consequence of data hiding on object performance?
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In the provided code example, what is the output after the method 'sum' is called twice?
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What is the purpose of inheritance in programming?
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In the syntax 'class Derived(Base1, Base2):', what does Base1 and Base2 represent?
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Which of the following statements about multi-level inheritance is true?
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What method will be executed when the following code is run: 'd = DogChild(); d.bark(); d.speak(); d.eat();'?
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Which class is known as the child class in the relationship defined by 'class Student(Person):'?
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How would you refer to the class that is inherited from another class?
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In the example of the 'Animal' class, what output will be produced by the 'speak()' method?
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What is a significant benefit of using inheritance in Python programming?
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What does the 'pass' statement signify in the 'Student' class definition?
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Given the statements, which correctly describes multiple inheritance in Python?
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What happens when you call the method 'add()' with two arguments in Python when there are two definitions of 'add()' in a class?
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Which statement is true regarding method overloading in Python?
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In the provided example, what is the output when calling 'print(obj.add(10, 20))' after implementing default arguments?
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What is the primary purpose of method overriding in Python?
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What will the child class execute when the method 'myMethod()' is called on an instance of the child class that overrides the parent class method?
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How can method overloading be achieved in Python using external libraries?
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What is the result of executing 'print(obj.add(10, 20, 30))' in the context of method overloading?
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Which of the following statements regarding method overloading and the example provided is false?
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What message indicates that an argument is missing when calling the 'add()' method in the overloaded example?
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What must be done to use the MultipleDispatch module in Python?
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What does the method getSalary() do in the SalesOfficer class?
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What is the purpose of using the super() function inside the init() method of the SalesOfficer class?
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How does data hiding contribute to object integrity?
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Which keyword is used in Python to denote a private class member for data hiding?
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What will be the output when the provided code is executed for the SalesOfficer object?
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What is the significance of overriding the getSalary() method in the SalesOfficer class?
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What happens when the del method is called?
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Which of the following best describes the concept of data hiding?
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What is a common outcome of implementing data hiding in programming?
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Which output will be produced when the Employee object's getSalary() method is invoked?
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Study Notes
Overview of OOP
- Object-Oriented Programming (OOP) centers around "objects" which combine data and behaviors.
- Objects are instances of classes, encapsulating attributes (data) and methods (functions).
- Classes serve as blueprints for creating objects, defining their structure and behavior.
- Encapsulation hides the internal state of objects while exposing necessary methods for interaction.
- Inheritance allows new classes to derive properties and methods from existing classes, promoting code reusability.
- Polymorphism enables treating objects of different classes as instances of a common superclass, achieved through method overriding and overloading.
- Abstraction simplifies complex systems by hiding unnecessary implementation details.
- Association describes relationships between objects, which can be one-to-one, one-to-many, or many-to-many.
OOP in Python
- Python supports OOP and allows for creating classes and objects easily.
- Classes are defined using the
class
keyword, followed by the class name and class attributes/methods. - The
__init__()
method, also known as the constructor, initializes object properties and is automatically called when creating an object. - Objects can be created by calling the class with parentheses.
- Python supports both single and multiple inheritance, allowing subclasses to inherit from one or more superclasses using the
super()
method. - Encapsulation is indicated by a single underscore
_
prefix, traditionally marking variables as private. - Abstraction is implemented through class interfaces, hiding implementation details while exposing essential functions.
Key Concepts of Classes and Objects
- A Class is a logical entity that combines attributes and methods.
- An Object represents a specific instance of a class, possessing state and behavior (e.g., properties and methods).
- Methods are functions associated with class instances, allowing objects to perform operations.
Inheritance
- Inheritance allows a child class to inherit properties and behaviors from a parent class.
- The parent class provides attributes and methods, while the child class can extend or modify these.
- Syntax for creating a child class involves specifying the parent class in parentheses during class definition.
- Inheritance promotes code reusability by allowing subclass creation based on existing classes.
Polymorphism
- Refers to a single task being performed in various ways.
- For example, an
Animal
class may define aspeak
method that different animal subclasses implement differently.
Encapsulation and Data Abstraction
- Encapsulation restricts access to certain methods and properties, reducing accidental modifications.
- Data abstraction hides the complexity of internal states, showing only essential functionalities.
Object as Function Arguments
- Objects can be passed as arguments to functions, allowing methods to manipulate their properties directly.
- Passing an object allows functions to operate on the actual instance rather than a copy.
- Modifications made to the object’s attributes within a function affect the original object.
Object as Return Values
- Functions can return objects, enabling the creation of new instances dynamically.
- Functions can also return primitive types like lists and tuples or even multiple values as tuples.
Built-in Class Attributes
- Common built-in class attributes include:
-
__dict__
: Contains the class's namespace. -
__doc__
: Holds the class documentation string. -
__name__
: Stores the class name. -
__module__
: Indicates the module in which the class is defined. -
__bases__
: A tuple of the class's base classes.
-
Summary of OOP Principles
-
Encapsulation, inheritance, polymorphism, and data abstraction are core principles enabling the design of modular and reusable code.
-
OOP provides an effective approach for modeling real-world entities and relationships.### Inheritance in Python
-
Single Inheritance: A derived class inherits from a single base class.
- Example: Class
Dog
inherits from classAnimal
, implementing thebark()
method while also having access tospeak()
fromAnimal
.
- Example: Class
-
Multi-Level Inheritance: A derived class inherits another derived class.
- Example: Class
DogChild
inherits classDog
, which in turn inherits classAnimal
. It can utilize methods from both parents and implement new ones likeeat()
.
- Example: Class
-
Multiple Inheritance: A child class inherits from multiple base classes.
- Example: Class
Derived
inherits fromCalculation1
andCalculation2
, allowing access to bothSummation
andMultiplication
methods.
- Example: Class
Method Overloading in Python
-
Method overloading is not supported directly in Python as seen in languages like Java or C++.
- When the same method name is defined multiple times in a class, only the latest definition is recognized.
-
Workaround for Overloading:
- Use default values for parameters to allow flexibility in the number of arguments.
- Example: Method
add(a=None, b=None, c=None)
works with one, two, or three arguments.
-
Using Multiple Dispatch: Install the
multipledispatch
module.- Allows defining multiple versions of a method with the same name but different signatures using the
@dispatch
decorator.
- Allows defining multiple versions of a method with the same name but different signatures using the
Method Overriding
-
Overriding allows derived classes to provide specific implementations of methods defined in base classes.
- Example: Class
Child
overridesmyMethod()
from classParent
.
- Example: Class
-
Using
super()
: This keyword is utilized to call methods from a parent class.- Example: In
SalesOfficer
,super().__init__(nm,sal)
initializes parent class attributes while overriding thegetSalary()
method to include incentives.
- Example: In
Data Hiding
-
Data hiding restricts access to certain parts of an object’s data to protect integrity and minimize complexity.
- Common feature in object-oriented programming that prevents unintended changes to data.
-
Implementation in Python: Class members with double underscores (e.g.,
__privateCounter
) become non-public, inaccessible from outside the class.- Accessing private members can be done through name mangling (e.g.,
_Solution__privateCounter
).
- Accessing private members can be done through name mangling (e.g.,
Advantages and Disadvantages of Data Hiding
-
Advantages:
- Protects volatile data from damage or misuse.
- Disconnects class objects from irrelevant data.
- Enhances security against unauthorized access.
-
Disadvantages:
- May lead to more complex code to implement data hiding.
- Can reduce performance due to obstacles in data linkage between visible and non-visible data.
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Description
Explore the fundamentals of Object-Oriented Programming (OOP) in this quiz, focusing on classes and objects. You'll learn about how objects are instances of classes and how they encapsulate data and behaviors. Test your understanding with concepts like attributes and methods through practical examples.