Python Multiple Choice Questions & Answers (MCQs) focuses on “Encapsulation”.
Q 1. Which of these is not a fundamental features of OOP?
A. Encapsulation
B. Instantiation
C. Inheritance
D. Polymorphism
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Answer:-B. InstantiationExplanation
Instantiation simply refers to creation of an instance of class. It is not a fundamental feature of OOP.Q 2. Which of the following is the most suitable definition for encapsulation?
A. Ability of a class to derive members of another class as a part of its own definition
B. Focuses on variables and passing of variables to functions
C. Means of bundling instance variables and methods in order to restrict access to certain class members
D. Allows for implementation of elegant software that is well designed and easily modified
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Answer:-C. Means of bundling instance variables and methods in order to restrict access to certain class membersExplanation
The values assigned by the constructor to the class members is used to create the object.Q 3. What will be the output of the following Python code?
class Demo:
def __init__(self):
self.a = 1
self.__b = 1
def display(self):
return self.__b
obj = Demo()
print(obj.a)
A. The program has an error because there isn’t any function to return self.a
B. The program has an error because b is private and display(self) is returning a private member
C. The program runs fine and 1 is printed
D. The program has an error as you can’t name a class member using __b
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Answer:-C. The program runs fine and 1 is printedExplanation
The program has no error because the class member which is public is printed. 1 is displayed. Execute in python shell to verify.Q 4. What will be the output of the following Python code?
class Demo:
def __init__(self):
self.a = 1
self.__b = 1
def display(self):
return self.__b
obj = Demo()
print(obj.__b)
A. The program has an error because b is private and hence can’t be printed
B. The program has an error because b is private and display(self) is returning a private member
C. The program has an error because there isn’t any function to return self.a
D. The program runs fine and 1 is printed
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Answer:-A. The program has an error because b is private and hence can’t be printedExplanation
Variables beginning with two underscores are said to be private members of the class and they can’t be accessed directly.
Q 5. Methods of a class that provide access to private members of the class are called as ______ and ______
A. getters/setters
B. __repr__/__str__
C. user-defined functions/in-built functions
D. __init__/__del__
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Answer:-A. getters/settersExplanation
The purpose of getters and setters is to get(return) and set(assign) private instance variables of a class.Q 6. Which of these is a private data field?
def Demo:
def __init__(self):
__a = 1
self.__b = 1
self.__c__ = 1
__d__= 1
A. __a
B. __b
C. __c__
D.__d__
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Answer:-B. __bExplanation
Variables such as self.__b are private members of the class.Q 7. What will be the output of the following Python code?
class Demo:
def __init__(self):
self.a = 1
self.__b = 1
def get(self):
return self.__b
obj = Demo()
print(obj.get())
A. The program has an error because there isn’t any function to return self.a
B. The program has an error because b is private and display(self) is returning a private member
C. The program has an error because b is private and hence can’t be printed
D. The program runs fine and 1 is printed
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Answer:-D. The program runs fine and 1 is printedExplanation
Here, get(self) is a member of the class. Hence, it can even return a private member of the class. Because of this reason, the program runs fine and 1 is printed.Q 8. What will be the output of the following Python code?
class Demo:
def __init__(self):
self.a = 1
self.__b = 1
def get(self):
return self.__b
obj = Demo()
obj.a=45
print(obj.a)
A. The program runs properly and prints 45
B. The program has an error because the value of members of a class can’t be changed from outside the class
C. The program runs properly and prints 1
D. The program has an error because the value of members outside a class can only be changed as self.a=45
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Answer:-A. The program runs properly and prints 45Explanation
It is possible to change the values of public class members using the object of the class.Q 9. Private members of a class cannot be accessed.
A. True
B. False
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Answer:-B. FalseExplanation
Private members of a class are accessible if written as follows: obj._Classname__privatemember. Such renaming of identifiers is called as name mangling.Q 10. The purpose of name mangling is to avoid unintentional access of private class members.
A. True
B. False
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Answer:-A. TrueExplanation
Name mangling prevents unintentional access of private members of a class, while still allowing access when needed. Unless the variable is accessed with its mangled name, it will not be found.Q 11. What will be the output of the following Python code?
class fruits:
def __init__(self):
self.price = 100
self.__bags = 5
def display(self):
print(self.__bags)
obj=fruits()
obj.display()
A. The program has an error because display() is trying to print a private class member
B. The program runs fine but nothing is printed
C. The program runs fine and 5 is printed
D. The program has an error because display() can’t be accessed
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Answer:-C. The program runs fine and 5 is printedExplanation
Private class members can be printed by methods which are members of the class.Q 12. What will be the output of the following Python code?
class student:
def __init__(self):
self.marks = 97
self.__cgpa = 8.7
def display(self):
print(self.marks)
obj=student()
print(obj._student__cgpa)
A. The program runs fine and 8.7 is printed
B. Error because private class members can’t be accessed
C. Error because the proper syntax for name mangling hasn’t been implemented
D. The program runs fine but nothing is printed
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Answer:-A. The program runs fine and 8.7 is printedExplanation
Name mangling has been properly implemented in the code given above and hence the program runs properly.Q 13. Which of the following is false about protected class members?
A. They begin with one underscore
B. They can be accessed by subclasses
C. They can be accessed by name mangling method
D. They can be accessed within a class
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Answer:-C. They can be accessed by name mangling methodExplanation
Protected class members can’t be accessed by name mangling.Q 14. What will be the output of the following Python code?
class objects:
def __init__(self):
self.colour = None
self._shape = “Circle”
def display(self, s):
self._shape = s
obj=objects()
print(obj._objects_shape)
A. The program runs fine because name mangling has been properly implemented
B. Error because the member shape is a protected member
C. Error because the proper syntax for name mangling hasn’t been implemented
D. Error because the member shape is a private member
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