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Question 1

What is an abstract class

Answer 1

An abstract class exists only so that other “concrete” classes can inherit from the abstract class

Question 2

What happens when you use the build-in function any() on a list?

Answer 2

the any() function returns True if all item in the list evaluates to True. Other wise, it returns False.

Question 3

what data structure does a binary tree degenerate to if it isn’t balanced properly?

Answer 3

Linked List

Question 4

What statement about static methods is true?

Answer 4

Static methods server mostly as utility methods or helper methods, since they can’t access or modify a class’s state

Question 5

What are attributes

Answer 5

Attributes are a way to hold data or describe a state for a class or instance of a class

Question 6

What is the term to describe this code?

count, fruit, price = (2, 'apple', 3.5)

Answer 6

Tuple unpacking

Question 7

What built-in list method would you use to remove items from a list?

Answer 7

“.pop()” method

Question 8

what is one of the most common use of Python’s sys library

Answer 8

To capture command-line arguments given at a file’s runtime

Question 9

what is the runtime of accessing a value in a dictionary by using its key?

Answer 9

O(1), also called constant time

Question 10

What is the correct syntax for defining a class called Game

Answer 10

class Game: pass

Question 11

what is the correct way to write a doctest

Answer 11

def sum(a, b):
“””
&raquo_space;> sum(4,3)
7

>>> sum(-4,5)
1
"""
return a + b

Question 12

What built-in Python data type is commonly used to represent a stack

Answer 12

list

Question 13

What would this expression return?

college_years = ['Freshman', 'Sophomore', 'Junior', 'Senior'] return list(enumerate(college_years, 2019))

Answer 13

[(2019, ‘Freshman’), (2020, ‘Sophomore’), (2021, ‘Junior’), (2022, ‘Senior’)]

Question 14

How doses defaultdict work

Answer 14

if you try to access a key in a dictionary that doesn’t exist, defaultdict will create a new key for you instead

Question 15

What is the correct syntax for defining a class called “Game” ,if it inherits from a parent class called “LogicGame”?

Answer 15

class Game(LogicGame): pass

Question 16

What is the purpose of the “self” keyword when defining or calling instance methods?

Answer 16

self refers to the instance whose method was called

Question 17

Which is NOT a characteristic of Named tuples

Answer 17

No import is needed to use named tuples because they are available in the standard library

Question 18

What is an instance Method?

Answer 18

Instance methods can modify the state of an instance or the state of its parent class.

Question 19

Which choice is the most syntactically correct example of the conditional branching?

Answer 19

num_people = 5

if num_people > 10:
print(“There is a lot of people in the pool.”)
elif num_people > 4:
print(“There are some people in the pool.”)
elif num_people > 0:
print(“There are a few people in the pool.”)
else:
print(“There is no one in the pool.”)

Question 20

Which statement does NOT describe the object-oriented programming concept of encapsulation?

Answer 20

It only allows the data to be changed by methods.

Question 21

What is the purpose of an If/else statement

Answer 21

An if/else exectues one chunk of code if the condition is true, but a different chunk of code if the condition is false

Question 22

what built-in Python data type is commonly used to represent a queue

Answer 22

list

Question 23

What is the correct syntax for instantiating a new object of the type Game

Answer 23

my_game = Game()

Question 24

what does the built-in map() function do?

Answer 24

it applies a function to each item in an iterable and returns the value of that function.

Question 25

If you don't explicitly return a value from a function, what happens?

Answer 25

If the return keyword is absent, the function will return None

Question 26

What is the purpose of the pass statement in Python?

Answer 26

it is a null operation used mainly as a placeholder in functions, classes, etc

Question 27

What is the term used to describe items that may be passed into a function

Answer 27

arguments

Question 28

Which collection type is used to associate values with unique keys

Answer 28

dictionary

Question 29

when does a for loop stop iterating

Answer 29

when it has assessed each item in the iterable it is working on or a break keyword is encountered

Question 30

Assuming the node is in a singly linked list what is the runtime complexity of searching for a specific node within a singly linked list

Answer 30

The runtime is O(n) because in the worst case, the node you are searching for is the last node, and every node in teh linked list must be visited.

Question 31

Given the following three list, how would you create a new list that matches the desired output printed below.. ``` fruits = ['Apples', 'Oranges', 'Bananas'] quantities = [5, 3, 4] prices = [1.50, 2.25, 0.89] ``` Desired output [('Apples', 5, 1.50), ('Oranges', 3, 2.25), ('Bananas', 4, 0.89)]

Answer 31

``` i = 0 output = [] for fruit in fruits: temp_qty = quantities[i] temp_price = prices[i] output.append((fruit, temp_qty, temp_price)) i += 1 return output ```

Question 32

What happens when you use the built-in function all() on a list

Answer 32

The all() function returns True if all items in the list evaluate to True Otherwise, it returns False

Question 33

What is the correct syntax for calling an instance method on a class named Game?

Answer 33

>>> dice = Game() | >>> dice.roll()

Question 34

What is the algorithmic paradigm of quick sort?

Answer 34

divide and conquer

Question 35

What is the runtime complexity of the list's built-in .append() method?

Answer 35

O(1), also called constant time

Question 36

What is the key difference between a set and a list?

Answer 36

A set is an unordered collection of unique items. A list is an ordered collection of non-unique items

Question 37

What is the definition of abstraction as applied to object-oriented Python?

Answer 37

Abstraction means the implementation is hidden from the user, and only the relevant data or information is shown

Question 38

What does this function print? ``` >>> def print_alpha_nums(abc_list, num_list): for char in abc_list: for num in num_list: print(char, num) return ``` print_alpha_nums(['a', 'b', 'c'], [1, 2, 3])

Answer 38

``` a 1 a 2 a 3 b 1 b 2 b 3 c 1 c 2 c 3 ```

Question 39

What is the correct syntax for calling an instance method on a class named Game?

Answer 39

my_game = Game() | my_game.roll_dice()

Question 40

Correct representation of doctest for function in Python

Answer 40

``` def sum(a, b): """ >>> a = 1 >>> b = 2 >>> sum(a, b) 3 """ ``` return a + b

Question 41

Suppose a Game class inherits from two parent classes: BoardGame and LogicGame. Which statement is true about the methods of an object instantiated from the Game class

Answer 41

An instance of the Game class will inherit whatever methods the BoardGame and LogicGame classes have

Question 42

What does calling namedtuple on a collection type return

Answer 42

a tuple subclass with iterable named fields

Question 43

What symbol(s) do you use to asses equality between two elements

Answer 43

==

Question 44

Review the code below. What is the correct syntax for changing the price to 1.5 ``` >>> fruit_info = { 'fruit': 'apple', 'count': 2, 'price': 3.5 } ```

Answer 44

fruit_info['price] = 1.5

Question 45

What value would be returned by this check for equality? 5 != 6

Answer 45

True

Question 46

What does a class's init() method do?

Answer 46

The __init__ method is a constructor method that is called automatically whenever a new object is created from a class. It sets the initial state of a new object

Question 47

What is meant by the phrase "space complexity"

Answer 47

The amount of space taken up in memory as a function of the input size

Question 48

What is the correct syntax for creating a variable that is bound to a dictionary?

Answer 48

fruit_info = {'fruit': 'apple', 'count': 2, 'price': 3.5}

Question 49

What is the proper way to write a list comprehension that represents all the keys in the dictionary? >>> fruits = {'Apples': 5, 'Oranges': 3, 'Bananas': 4}

Answer 49

fruit_names = [x for x in fruits.keys()}

Question 50

What is the algorithmic paradigm of quick sort?

Answer 50

divide and conquer

Question 51

What is the purpose of the self keyword when defining or calling methods on an instance of an object

Answer 51

self refers to the instance whose method was called

Question 52

What statement about a class method is true

Answer 52

A class method can modify the state of the class but they can't directly modify the state of an instance that inherits from that class

Question 53

What does it mean for a function to have linear runtime?

Answer 53

The amount of time it takes the function to complete grows linearly ass the input size increases

Question 54

What is the proper way to define a function

Answer 54

def get_max_num(list_of_nums): #body of function goes here

Question 55

according to the PEP 8 coding style guidelines, how should constant values be named in Python

Answer 55

in all caps with underscores separating words -- e.g. MAX_VALUE = 255

Question 56

Describe the functionality of a deque

Answer 56

A deque adds items at either or both ends, and remove items at either or both ends

Question 57

What is the correct syntax for creating a variable that is bound to a set?

Answer 57

myset = {0, 'apple', 3.5}

Question 58

What is the correct syntax for defining an __init__() method that takes no parameters

Answer 58

``` def __init__(self): pass ```

Question 59

Which statement about the class methods is true

Answer 59

A class method can modify the state of the class but it cannot directly modify the state of an instance to hat inherits from that class

Question 60

Which of the following is True about how numeric data would be organized in a binary Search tree

Answer 60

For any given Node in a binary Search Tree, the child node to the left is less that the value of the given node and the child node to its right is greater that the given node

Question 61

Why would you use a decorator

Answer 61

You use the decorator to alter the functionality of a function without having to modify the functions code

Question 62

When would you use a for loop?

Answer 62

When you need to check every element in an iterable of known length

Question 63

What is the most self-descriptive way to define a function that calculates sales tax on a purchase?

Answer 63

``` def sales_tax(amount): '''Calculates the sales tax of a purchase. Takes in a float representing the subtotal as an argument and returns a float representing the sales tax.''' ```

Question 64

What would happen if you did not alter the state of the element that an algorithm is operating on recursively

Answer 64

You would get a RuntimeError: maximum recursion depth exceeded.

Question 65

What is the runtime complexity of searching for an item in a binary search tree?

Answer 65

the runtime for searching a binary search tree is generally O(h) where h is the height of the tree

Question 66

Why would you use mixin

Answer 66

If you have many classes that all need to have the same functionality you'd use a mixin to define that functionality

Question 67

What is the runtime complexity of adding an item to a stack and removing an item from a stack?

Answer 67

Add items to a stack in O(1) or constant and remove items from a stack on O(n) time or linear

Question 68

What does calling namedtuple on a collection type return

Answer 68

a tuple subclass with iterable named fields

Question 69

which statement accurately describes how items are added to and removed from a stack

Answer 69

a stack adds items to the top and removes items from the top

Question 70

what is the base cases in a recursive function?

Answer 70

A base case is the condition that allows the algorithm to stop recursing. it is usually a problem that is small enough to solve directly