Question 1

Which of the following statements is false?

Accepted Answer

A)  Python provides two built-in functions-issubclass and isinstance-for testing "is a" relationships. 
B)  Function issubclass determines whether one class inherits from another. 
C)  Function isinstance determines whether an object has an "is a" relationship with a specific type. 
D)  If SalariedCommissionEmployee inherits from CommissionEmployee, and if object s is a SalariedCommissionEmployee, then the following snippet results are correct:
In [19]: isinstance(s, CommissionEmployee)
Out[19]: False
In [20]: isinstance(s, SalariedCommissionEmployee)
Out[20]: True 
A)  Python provides two built-in functions-issubclass and isinstance-for testing "is a" relationships. 
B)  Function issubclass determines whether one class inherits from another. 
C)  Function isinstance determines whether an object has an "is a" relationship with a specific type. 
D)  If SalariedCommissionEmployee inherits from CommissionEmployee, and if object s is a SalariedCommissionEmployee, then the following snippet results are correct:
In [19]: isinstance(s, CommissionEmployee)
Out[19]: False
In [20]: isinstance(s, SalariedCommissionEmployee)
Out[20]: True D

Question 2

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  Classes are new function types. 
B)  Most applications you'll build for your own use will commonly use either no custom classes or just a few. 
C)  You can contribute your custom classes to the Python open-source community, but you are not obligated to do so. Organizations often have policies and procedures related to open-sourcing code. 
D)  All of the above statements are true. 
A)  Classes are new function types. 
B)  Most applications you'll build for your own use will commonly use either no custom classes or just a few. 
C)  You can contribute your custom classes to the Python open-source community, but you are not obligated to do so. Organizations often have policies and procedures related to open-sourcing code. 
D)  All of the above statements are true. A

Question 3

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  When you call a method for a specific object, Python implicitly passes a reference to that object as the method's first argument, so all methods of a class must specify at least one parameter. 
B)  All methods must have a first parameter xe "self in a method's parameter list"self-a class's methods must use that reference to access the object's attributes and other methods. 
C)  When an object of a class is created, it does not yet have any attributes. They're added dynamically via assignments, typically of the form self.attribute_name = value. 
D)  All of the above statements are true. 
A)  When you call a method for a specific object, Python implicitly passes a reference to that object as the method's first argument, so all methods of a class must specify at least one parameter. 
B)  All methods must have a first parameter xe "self in a method's parameter list"self-a class's methods must use that reference to access the object's attributes and other methods. 
C)  When an object of a class is created, it does not yet have any attributes. They're added dynamically via assignments, typically of the form self.attribute_name = value. 
D)  All of the above statements are true. B

Question 4

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  Each property defines a getter method which gets (that is, returns) a data attribute's value and can optionally define a setter method which sets a data attribute's value. 
B)  The @property decorator precedes a property's xe "getter method:decorator"getter method, which receives only a self parameter. 
C)  Behind the scenes, a decorator adds code to the decorated function to enable the function to work with data attribute syntax. 
D)  All of the above statements are true. 
A)  Each property defines a getter method which gets (that is, returns) a data attribute's value and can optionally define a setter method which sets a data attribute's value. 
B)  The @property decorator precedes a property's xe "getter method:decorator"getter method, which receives only a self parameter. 
C)  Behind the scenes, a decorator adds code to the decorated function to enable the function to work with data attribute syntax. 
D)  All of the above statements are true.

Question 5

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  A class can also support setting its attribute values individually via its properties. Assuming hour is a property of wake_up's class, the following statement changes an hour property value to 6:
Wake_up.hour = 6 
B)  Though the statement snippet in Part (a) appears to simply assign a value to a data attribute, it's actually a call to an hour method that takes 6 as an argument. 
C)  The hour method mentioned in Part (b) can validate the value, then assign it to a corresponding data attribute (which we might name _hour, for example). 
D)  Each of the above statements is true. 
A)  A class can also support setting its attribute values individually via its properties. Assuming hour is a property of wake_up's class, the following statement changes an hour property value to 6:
Wake_up.hour = 6 
B)  Though the statement snippet in Part (a) appears to simply assign a value to a data attribute, it's actually a call to an hour method that takes 6 as an argument. 
C)  The hour method mentioned in Part (b) can validate the value, then assign it to a corresponding data attribute (which we might name _hour, for example). 
D)  Each of the above statements is true.

Question 6

Properties look like ________ to client-code programmers, but control the manner in which they get and modify an object's data.

Accepted Answer

A)  function calls 
B)  method calls 
C)  data attributes 
D)  None of the above 
A)  function calls 
B)  method calls 
C)  data attributes 
D)  None of the above

Question 7

Which of the following statements is false?

Accepted Answer

A)  Sometimes, an attribute should be shared by all objects of a class. A class attribute (also called a class variable) represents class-wide information-it belongs to the class, not to a specific object of that class. 
B)  You define a class attribute by assigning a value to it inside the class's definition, but not inside any of the class's methods or properties (in which case, they'd be local variables). 
C)  Class attributes are typically accessed through any object of the class. 
D)  Class attributes exist as soon as you import their class's definition. 
A)  Sometimes, an attribute should be shared by all objects of a class. A class attribute (also called a class variable) represents class-wide information-it belongs to the class, not to a specific object of that class. 
B)  You define a class attribute by assigning a value to it inside the class's definition, but not inside any of the class's methods or properties (in which case, they'd be local variables). 
C)  Class attributes are typically accessed through any object of the class. 
D)  Class attributes exist as soon as you import their class's definition.

Question 8

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  Polymorphism enables you to conveniently xe "program "in the general""program "in the general" rather than "xe "program "in the specific""in the specific." 
B)  With polymorphism, you simply send the same method call to objects possibly of many different types. Each object responds by "doing the right thing" for objects of its type. So the same method call takes on many forms, hence the term "poly-morphism." 
C)  In Python, as in other major object-oriented programming languages, you can implement polymorphism only via inheritance. 
D)  All of the above statements are true. 
A)  Polymorphism enables you to conveniently xe "program "in the general""program "in the general" rather than "xe "program "in the specific""in the specific." 
B)  With polymorphism, you simply send the same method call to objects possibly of many different types. Each object responds by "doing the right thing" for objects of its type. So the same method call takes on many forms, hence the term "poly-morphism." 
C)  In Python, as in other major object-oriented programming languages, you can implement polymorphism only via inheritance. 
D)  All of the above statements are true.

Question 9

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  All classes inherit from object directly or indirectly, so they all inherit the default methods for obtaining string representations that print can display. 
B)  Python also has duck typing, which the Python documentation describes as: A programming style which does not look at an object's type to determine if it has the right interface; instead, the method or attribute is simply called or used ("If it looks like a duck and quacks like a duck, it must be a duck."). 
C)  When Python processes an object at execution time, its type does not matter. As long as the object has the data attribute, property or method (with the appropriate parameters) you wish to access, the code will work. 
D)  All of the above statements are true. 
A)  All classes inherit from object directly or indirectly, so they all inherit the default methods for obtaining string representations that print can display. 
B)  Python also has duck typing, which the Python documentation describes as: A programming style which does not look at an object's type to determine if it has the right interface; instead, the method or attribute is simply called or used ("If it looks like a duck and quacks like a duck, it must be a duck."). 
C)  When Python processes an object at execution time, its type does not matter. As long as the object has the data attribute, property or method (with the appropriate parameters) you wish to access, the code will work. 
D)  All of the above statements are true.

Question 10

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  It may seem that providing properties with both setters and getters has no benefit over accessing the data attributes directly, but there are subtle differences. 
B)  A getter seems to allow clients to read the data at will, but the getter can control the formatting of the data. 
C)  A setter can scrutinize attempts to modify the value of a data attribute to prevent the data from being set to an invalid value. 
D)  All of the above statements are true. 
A)  It may seem that providing properties with both setters and getters has no benefit over accessing the data attributes directly, but there are subtle differences. 
B)  A getter seems to allow clients to read the data at will, but the getter can control the formatting of the data. 
C)  A setter can scrutinize attempts to modify the value of a data attribute to prevent the data from being set to an invalid value. 
D)  All of the above statements are true.

Question 11

The following code and traceback shows that our class Time's hour property xe "validate data"validates the values you assign to it: In [10]: wake_up.hour = 100 --------------------------------------------------------------------- ValueError Traceback (most recent call last) in () ----> 1 wake_up.hour = 100 ~/Documents/examples/ch10/timewithproperties.py in hour(self, hour) 20 """Set the hour.""" 21 if not (0 <= hour < 24): ---> 22 raise ValueError(f'Hour ({hour}) must be 0-23') 23 24 self._hour = hour ValueError: Hour (100) must be 0-23 Which of the following statements a), b) or c) is false?

Accepted Answer

A)  The code attempts to set the hour property to an invalid value. 
B)  The code checks that the hour property is in the range 0 through 24. 
C)  The value 100 is out of range so the code raises a ValueError. 
D)  All of the above statements are true. 
A)  The code attempts to set the hour property to an invalid value. 
B)  The code checks that the hour property is in the range 0 through 24. 
C)  The value 100 is out of range so the code raises a ValueError. 
D)  All of the above statements are true.

Question 12

Most object-oriented programming languages enable you to encapsulate (or hide) an object's data from the client code. Such data in these languages is said to be ________ data.

Accepted Answer

A)  public 
B)  protected 
C)  private 
D)  None of the above 
A)  public 
B)  protected 
C)  private 
D)  None of the above

Question 13

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  You'll use lots of classes created by other people. 
B)  You can create your own custom classes. 
C)  Core technologies of object-oriented programming are classes, objects, inheritance and polymorphism. 
D)  All of the above statements are true. 
A)  You'll use lots of classes created by other people. 
B)  You can create your own custom classes. 
C)  Core technologies of object-oriented programming are classes, objects, inheritance and polymorphism. 
D)  All of the above statements are true.

Question 14

Assume that class Time's __init__ method receives hour, minute and second parameters. Based on the following code: wake_up = Time(hour=6, minute=30)
Which of the following statements is true?

Accepted Answer

A)  If at least two arguments have default arguments, the third automatically defaults to zero. 
B)  Any omitted argument is automatically set to zero. 
C)  second has a default argument in the __init__ method's definition. 
D)  None of the above. 
A)  If at least two arguments have default arguments, the third automatically defaults to zero. 
B)  Any omitted argument is automatically set to zero. 
C)  second has a default argument in the __init__ method's definition. 
D)  None of the above.

Question 15

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  When you pass an object to built-in function xe "built-in function:repr"xe "repr built-in function"repr-which happens implicitly when you evaluate a variable in an IPython session-the corresponding class's __repr__ special method is called to get the "official" string representation of the object. 
B)  Typically the string returned by __repr__ looks like a constructor expression that creates and initializes the object, such as:
'Time(hour=6, minute=30, second=0)' 
C)  Python has a built-in function eval that could receive the string shown in Part (b) as an argument and use it to create and initialize a Time object containing values specified in the string. 
D)  All of the above statements are true. 
A)  When you pass an object to built-in function xe "built-in function:repr"xe "repr built-in function"repr-which happens implicitly when you evaluate a variable in an IPython session-the corresponding class's __repr__ special method is called to get the "official" string representation of the object. 
B)  Typically the string returned by __repr__ looks like a constructor expression that creates and initializes the object, such as:
'Time(hour=6, minute=30, second=0)' 
C)  Python has a built-in function eval that could receive the string shown in Part (b) as an argument and use it to create and initialize a Time object containing values specified in the string. 
D)  All of the above statements are true.

Question 16

Which of the following statements is false?

Accepted Answer

A)  The vast majority of object-oriented programming you'll do in Python is object-based programming in which you primarily use objects of new custom classes you create. 
B)  To take maximum advantage of Python you must familiarize yourself with lots of preexisting classes. 
C)  Over the years, the Python open-source community has crafted an enormous number of valuable classes and packaged them into class libraries, available on the Internet at sites like xe "GitHub"GitHub, xe "BitBucket"BitBucket, xe "SourceForge"SourceForge and more. This makes it easy for you to reuse existing classes rather than "reinventing the wheel." 
D)  Widely used open-source library classes are more likely to be thoroughly tested, bug free, performance tuned and portable across a wide range of devices, operating systems and Python versions. 
A)  The vast majority of object-oriented programming you'll do in Python is object-based programming in which you primarily use objects of new custom classes you create. 
B)  To take maximum advantage of Python you must familiarize yourself with lots of preexisting classes. 
C)  Over the years, the Python open-source community has crafted an enormous number of valuable classes and packaged them into class libraries, available on the Internet at sites like xe "GitHub"GitHub, xe "BitBucket"BitBucket, xe "SourceForge"SourceForge and more. This makes it easy for you to reuse existing classes rather than "reinventing the wheel." 
D)  Widely used open-source library classes are more likely to be thoroughly tested, bug free, performance tuned and portable across a wide range of devices, operating systems and Python versions.

Question 17

Which of the following statements a), b) or c) is false?

Accepted Answer

A)  Everything in Python is an object. 
B)  Just as houses are built from blueprints, classes are built from objects-one of the core technologies of object-oriented programming. 
C)  Building a new object from even a large class is simple-you typically write one statement. 
D)  All of the above statements are true. 
A)  Everything in Python is an object. 
B)  Just as houses are built from blueprints, classes are built from objects-one of the core technologies of object-oriented programming. 
C)  Building a new object from even a large class is simple-you typically write one statement. 
D)  All of the above statements are true.

Question 18

Properties are implemented as ________, so they may contain additional logic, such as specifying the format in which to return a data attribute's value or validating a new value before using it to modify a data attribute.

Accepted Answer

A)  functions 
B)  suites 
C)  classes 
D)  methods 
A)  functions 
B)  suites 
C)  classes 
D)  methods

Question 19

Which of the following statements about code snippets that use class Account is false?

Accepted Answer

A)  The following code uses a constructor expression to create an Account object and initialize it with an account holder's name (a string) and balance (a Decimal):
Account1 = Account('John Green', Decimal('50.00')) 
B)  The following expressions access an Account object's name and balance xe "class:attribute"xe "attribute:of a class"xe "attribute:of a class"attributes:
Account1.name
Account1.balance 
C)  The following snippets deposit an amount into an Account and access the new balance:
Account1.deposit(Decimal('25.53'))
Account1.balance 
D)  All of the above statements are true. 
A)  The following code uses a constructor expression to create an Account object and initialize it with an account holder's name (a string) and balance (a Decimal):
Account1 = Account('John Green', Decimal('50.00')) 
B)  The following expressions access an Account object's name and balance xe "class:attribute"xe "attribute:of a class"xe "attribute:of a class"attributes:
Account1.name
Account1.balance 
C)  The following snippets deposit an amount into an Account and access the new balance:
Account1.deposit(Decimal('25.53'))
Account1.balance 
D)  All of the above statements are true.

Question 20

When you evaluate a variable in IPython it calls the corresponding object's ________ special method to produce a string representation of the object.

Accepted Answer

A)  __init__ 
B)  __str__ 
C)  __string__ 
D)  xe "object class:__repr__ special method"xe "__repr__ special method of class object[repr__ special method of class object]"__repr__ 
A)  __init__ 
B)  __str__ 
C)  __string__ 
D)  xe "object class:__repr__ special method"xe "__repr__ special method of class object[repr__ special method of class object]"__repr__

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Properties look like ________ to client-code programmers, but control the manner in which they get and modify an object's data.

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Most object-oriented programming languages enable you to encapsulate (or hide) an object's data from the client code. Such data in these languages is said to be ________ data.

Which of the following statements a), b) or c) is false?

Assume that class Time's init method receives hour, minute and second parameters. Based on the following code: wake_up = Time(hour=6, minute=30) Which of the following statements is true?

Which of the following statements a), b) or c) is false?

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Properties are implemented as ________, so they may contain additional logic, such as specifying the format in which to return a data attribute's value or validating a new value before using it to modify a data attribute.

Which of the following statements about code snippets that use class Account is false?

When you evaluate a variable in IPython it calls the corresponding object's ________ special method to produce a string representation of the object.

Introduction to Computers and Python

Introduction to Python Programming

Control Statements and Program Development

Functions

Sequences: Lists and Tuples

Dictionaries and Sets

Array-Oriented Programming With Num

Strings: a Deeper Look

Files and Exceptions

Computer Science Thinking: Recursion, Searching, Sorting and Big O

Natural Language Processing

Data Mining Twitter

Ibm Watson and Cognitive Computing

Machine Learning: Classification, Regression and Clustering

Deep Learning

Big Data: Hadoop, Spark, Nosql and Iot

Filters

Exam 10: Object-Oriented Programming

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Properties look like ________ to client-code programmers, but control the manner in which they get and modify an object's data.

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Which of the following statements a), b) or c) is false?

Most object-oriented programming languages enable you to encapsulate (or hide) an object's data from the client code. Such data in these languages is said to be ________ data.

Which of the following statements a), b) or c) is false?

Assume that class Time's __init__ method receives hour, minute and second parameters. Based on the following code: wake_up = Time(hour=6, minute=30) Which of the following statements is true?

Which of the following statements a), b) or c) is false?

Which of the following statements is false?

Which of the following statements a), b) or c) is false?

Properties are implemented as ________, so they may contain additional logic, such as specifying the format in which to return a data attribute's value or validating a new value before using it to modify a data attribute.

Which of the following statements about code snippets that use class Account is false?

When you evaluate a variable in IPython it calls the corresponding object's ________ special method to produce a string representation of the object.

Introduction to Computers and Python

Introduction to Python Programming

Control Statements and Program Development

Functions

Sequences: Lists and Tuples

Dictionaries and Sets

Array-Oriented Programming With Num

Strings: a Deeper Look

Files and Exceptions

Computer Science Thinking: Recursion, Searching, Sorting and Big O

Natural Language Processing

Data Mining Twitter

Ibm Watson and Cognitive Computing

Machine Learning: Classification, Regression and Clustering

Deep Learning

Big Data: Hadoop, Spark, Nosql and Iot

Filters

Assume that class Time's init method receives hour, minute and second parameters. Based on the following code: wake_up = Time(hour=6, minute=30) Which of the following statements is true?