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03 - Instantiation

1. From an object oriented programming perspective, a class is the blueprint for an ………………

Note: The following is OOP in Java - worth a read as you expose yourselves to different languages.

Object Oriented Programming with Java from Jussi Pohjolainen

aptitude variable

attribute

archtype

object

2. A class simply describes what an object will look like and how it will behave.

FALSE

TRUE

3. Therefore instantiation is the process of taking a class definition and ………………………………………..

So, at it’s core, instantiation is the process of taking a class, and creating an object from it that you can actually use in your program. (or simply, creating an object from a class)

creating an object that you can use in a program

None of the above

creating attributes and methods that attach to the object

creating a class that acts as an object

4. An object is an instance of a class, and may be called a class instance or class object; instantiation is then also known as ………………………

attribute creation

mechanation

construction

objection

5. Not all classes can be instantiated – ………………………. cannot be instantiated, while classes that can be instantiated are called concrete classes

finite classes

None of the above

abstract classes

transparent classes

6. Like constructors in C++, we’ve got the ……………..in Python. This function gets called every time you instantiate the class. Please refer the below example to view a complete Python class.

class EmployeeData:

    def __init__(self, sal=0, age=0):
        self.sal = sal
        self.age = age

    def getData(self):
        print("{0}+{1}j".format(self.sal,self.age))

construct() method

__init__() method

def() method

getattribute() method

7. Which Of The Following Represents A Distinctly Identifiable Entity In The Real World?

A method

A class

An attribute

An object

8. Which Of The Following Keywords Mark The Beginning Of The Class Definition?

class

return

def

All of the above can be used

9. Which Of The Following Is Required To Create A New Instance Of The Class?

A class

A constructor

A 'None' method

A value returning method

10. Which Of The Following Statements Is Most Accurate For The Declaration X = Circle()?

You can assign an int value to x (e.g radius of circle)

x contains a reference to a Circle object.

All of the above are valid

x contains an int value.

11. What is the output of the following code snippet?

class Sales:
    def __init__(self, id):
        self.id = id
        id = 100

val = Sales(123)
print (val.id)

123

None of the above

100

Syntax error - this program will not run

12. Every object in Python has an attribute denoted by __dict__. This dictionary/dictionary-like object contains all the attributes defined for the object itself. It ……………………

maps the attribute name to the class

maps the value to the class

maps the attribute name to its value.

maps the object to the value as well as to the class methods

13. What is the output of the following code that makes use of __dict__?

class Person:
    def __init__(self, id):
        self.id = id

sam = Person(100)

sam.__dict__['age'] = 49

print (sam.age + len(sam.__dict__))

Object.__class__.__dict__ - python object model and friends - with examples from Robert Lujo

14. Which Of The Following Statements Can Be Used To Check, Whether An Object “Obj” Is An Instance Of Class A Or Not?

A.isinstance(obj)

obj.isinstance(A)

isinstance(A, obj)

isinstance(obj, A)

15. In the following code, where is the object being created and what is the object?

# A simple example class
class Test:
     
    # A sample method 
    def fun(self):
        print("Hello")
 
# Driver code
obj = Test()
obj.fun()

obj = Test() creates the object named 'obj'

class Test: creates the object 'Test'

None of the above

class Test: creates the 'test' object called 'obj'

16. What is the output of the following? Note particularly the last line - obj.fun()

# A simple example class
class Test:
     
    # A sample method 
    def fun(self):
        print("Hello")
 
# Driver code
obj = Test()
obj.fun()

fun

self

Error

Hello

17. If we have a method which takes no arguments, then we still have to have one argument – the self

TRUE

FALSE

18. The __init__ method is similar to constructors in C++ and Java. It is run as soon as an ……………………………….. is instantiated.

# A Sample class with init method
class Person:
 
    # init method or constructor 
    def __init__(self, name):
        self.name = name
 
    # Sample Method 
    def say_hi(self):
        print('Hello, my name is', self.name)
 
p = Person('Ruth Marvin')
p.say_hi()

attribtue of an object

attribute of a class

None of the above

object of a class

19. Here, we define the __init__ method as taking one parameter ……………………………..(along with the usual self)

Ruth Marvin

self

name

20. What is the output from the following code?

class fruits:
    def __init__(self, price):
        self.price = price
obj=fruits(50)
 
obj.quantity=10
obj.bags=2
 
print(obj.quantity+len(obj.__dict__))

21. In the following code, fill in the blanks for d.kind.

class Dog:

    kind = 'canine'         # class variable shared by all instances

    def __init__(self, name):
        self.name = name    # instance variable unique to each instance

>>> d = Dog('Fido')
>>> e = Dog('Buddy')
>>> d.kind                  # ................?
'canine'
>>> e.kind                  # shared by all dogs
'canine'
>>> d.name                  # unique to d
'Fido'
>>> e.name                  # unique to e
'Buddy'

unique to e

unique to all cats

Shared by all dogs

unique to d

22. It is good practice to define the attributes of an instance right after its creation.

TRUE

FALSE

23. __init__ is a method which is immediately and automatically called after an instance has been created

TRUE

FALSE

24. There is no explicit constructor or destructor method in Python, as they are known in C++ and Java but…(read the following excerpt) and decide whether it is true or false.

The __init__ method can be anywhere in a class definition, but it is usually the first method of a class, i.e. it follows right after the class header

FALSE

TRUE

25. Guido van Rossum has designed the language according to the principle "first-class everything". In fact - everything in Python is a class.

TRUE

FALSE

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