CS 220 Midterm 2

What does the following code print? mapping = {} my_list = [] keys = [ 'k0', 'k1', 'k2' ] for k in keys: mapping[k] = my_list for i in range(3): k = keys[i] mapping[k].append(i) print(mapping['k0'], mapping['k1']) a. None None b. [0] [1] c. [1] [2] d. [0, 1, 2] [0, 1, 2] e. k0 k1

d. [0, 1, 2] [0, 1, 2]

What is the value of x after this code is run? [options on next page] orig = [1, [2, 3]] x = orig y = copy.copy(orig) y[0] = 4 y[1][0] = 5 y[1][1] = 6 print(x) 6 a. [1, [2, 3]] b. [4, [2, 3]] c. [4, [5, 6]] d. [1, [5, 6]]

d. [1, [5, 6]]

Which call to foo will NOT cause an AssertionError? [see options on next page] def foo(x, y): assert type(x) == int and type(y) == int assert x % 2 == 0 and x > y return x y a. foo("4", 2) b. foo(2, 2) c. foo(3, 2) d. foo(4, -3) e. foo(4, 2.0)

d. foo(4, 3)

What is printed? data = [["alice", "in", "wonderland"], ["a","b","c"], ["hello"]] print(data[2][0][1]) a. a b. hello c. c d. o e. e

d. o

Consider the following dictionary. person = {} person['name'] = 'Vinodh Balasubramanian' person['address'] = { 'street': '1, Gangai Amman Koil Street', 'city': 'Chennai', 'state': 'Tamil Nadu', 'zip': 600014 } How will you access the name of the city (i.e., Chennai) that this person lives in? a. person['city'] b. person[1]['city'] c. person['address'][1] d. person['address']['city']

d. person['address']['city']

What is the output of the above snippet? mapping = {} for i in range(3): for j in range(2): mapping[(i,j)] = i + j print(len(mapping), mapping[(1,1)]) a. 2 2 b. 3 1 c. 3 2 d. 6 1 e. 6 2

e. 6 2

10. Which of the following is the correct way to the attribute x in Point p? Point = namedtuple("Point", ['x', 'y']) p = Point(10, 20) a. p{x} b. p("x") c. p[x] d. p["x"] e. p.x

e. p.x

15. Which of the following will generate a dictionary with name to age mapping? players = [{"name":"Alia", "jersey":17,"age":20}, {"name":"Brianna", "jersey":6, "age":19}, {"name":"Carl", "jersey":10, "age":21} ] A. {k:v for (k, players["age"]) in players} B. {d["name"]:d["age"] for d in players} C. {d[0]:d[2] for d in players" D. {k:v for (k, v) in players.items()}

{d["name"]:d["age"] for d in players}

1. Using asserts is most useful for dealing with which category of errors? A. syntax B. runtime C. semantic D. exceptional 2. What is true about frames? A. there is always exactly one frame per function de nition B. every object is associated with exactly one frame C. all of the above D. none of the above

1. C. semantic 2. D. none of the above

For the following, assume the initial code executed is as follows (if a question contains code that modi es the objects, those changes should not be considered in other questions): gens = ["g1", "g2", "g3"] movs = [{"title": "A", "year": 17, "style": "short", "genres": ["g1"]}] def chk(movies, year): assert type(year) == int assert type(movies[0]) == dict # TODO: finish this function 14. Which call will NOT cause an AssertionError? A. chk(gens, "18") B. chk(gens, 18) C. chk(movs, "18") D. chk(movs, 18) 16. What should replace ???? to trigger the most informative exceptions when year isn't an iont? def filter_by_year(movies, year): if type(year) != int: ???? # TODO: finish writing this function A. return TypeError("year shoud be int") B. return ValueError("year shoud be int") C. raise TypeError("year shoud be int") D. raise ValueError("year shoud be int")

14. D. chk(movs, 18) 16. C. raise TypeError("year shoud be int")

For each question in this section, assume that the initial code executed is as follows: vaccinations = [ {"iso": "ALB", "vacc": "Pfizer, Sinovac", "vacc months": ["Jan", "Feb", "Mar", "May"], "vacc counts": [549, 6728, 110015, 650001]}, {"iso": "FRO", "vacc": "Moderna, Pfizer", "vacc months": ["Apr"], "vacc counts": [15531]}, {"iso": "VEN", "vacc": "Sputnik V", "vacc months": ["Feb", "Apr", "May", "Jun"], "vacc counts": [157, 10770, 316015, 620437]}, {"iso": "ZMB", "vacc": "Oxford", "vacc months": ["Jun"], "vacc counts": [148304]} ] 16. What does the following evaluate to? vaccinations[0]["vacc"][1:3] A. 6728, 110015 B. 6728, 110015, 650001 C. fi D. fiz 17. What does the following evaluate to? vaccinations[-2]["vacc months"].index("May") A. 3 B. 5 C. May D. 2 E. IndexError 18. What does the following evaluate to? vaccinations[0]["vacc months"] + vaccinations[-1]["vacc months"] A. `Jan, Feb, Mar, May, Jun' B. [`Jan', `Feb', `Mar', `May', `Jun'] C. [`Jan', `Feb', `Mar', `May', [`Jun']] D. [`Mar', `Apr', `Jun', `Jun']

16. fi 17. D. 2 18. B. [`Jan', `Feb', `Mar', `May', `Jun']

from collections import namedtuple Player = namedtuple("Player", ["name", "rating", "club", "country"]) hazard = Player(name="Eden Hazard", rating=91, club="Chelsea", country="Belgium") pulisic = Player(name="Christian Pulisic", club="Chelsea", rating=79, country="United States") messi = Player(name="Lionel Messi", club="Barcelona", country="Argentina", rating=94) players = ["Kevin De Bruyne", "Christiano Ronaldo", "Harry Kane", "Hugo Lloris", "Don Smart"] salah = {} salah["name"] = "Mo Salah" salah["nationality"] = "Egypt" salah["jersey"] = 11 salah["nationality"] = "Egypt" 17. What does pulisic.club evaluate to? A. \Chelsea" B. Error C. 79 D. club E. rating 18. How can we switch Eden Hazard's club to Real Madrid? A. hazard.club = "Real Madrid" B. hazard[1] = "Read Madrid" C. hazard["club"] = "Read Madrid" D. hazard = Player(name=hazard.name, rating=hazard.rating, club="Real Madrid", country=hazard.country) 19. How can we get only the rst 3 players in players? A. players[3] B. players[0:3] C. players[0:2] D. players(3) E. players[0, 1, 2] 20. What is len(salah)? Careful! A. 3 B. 4 C. 5 D. 6 E. 8 21. Which data type would you not be able to use if you wanted to store hazard, pulisic, and messi in a variable called data and access them using data[0], data[1], and data[2]? A. dict B. list C. set D. tuple

17. A. \Chelsea" 18.D. hazard = Player(name=hazard.name, rating=hazard.rating, club="Real Madrid", country=hazard.country) 19. B. players[0:3] 20. A. 3 21. C. set

airbnb = [{"name":"A", "room_id":837, "start_year":2021, "reviews":[""]}, {"name":"B", "room_id":389, "start_year":2021, "reviews":["*","","**"]}, {"name":"C", "room_id":108, "start_year":2021, "reviews":["***","**"]}, {"name":"D", "room_id":237, "start_year":2020, "reviews":["*"]}, {"name":"E", "room_id":278, "start_year":2020, "reviews":["***","**","***"]}, ] 17. What does the following evaluate to? airbnb[-1]["reviews"][1] A. "**" B. "***" C. ["***"] D. ["***", "**", "***"] E. "reviews" 18. What does the following evaluate to? airbnb[2]["reviews"].index(airbnb[1]["reviews"][2]) A. 0 B. 1 C. 2 D. "**" E. "" 19. What does the following evaluate to? airbnb[1]["reviews"][:1] + airbnb[2]["reviews"][1:] A. ["*", "", "**"] B. ["*", "**"] C. ["*"] D. f"reviews": ["*", "**"]g 20. Which of the following would generate a list of airbnb listing names, which have room id greater than 250? A. fkey: val for key, val in airbnb.items() if item["room id"] > 250g B. [item if item["room id"] > 250 for item in airbnb] C. [item["name"] for item in airbnb if item["room id"] > 250] D. [item for item in airbnb if item["room id"] > 250]

17.A. "**" 18. B. 1 19. B. ["*", "**"] 20. C. [item["name"] for item in airbnb if item["room id"] > 250]

For the next few questions consider the following code that prints a grid displaying the areas where hurricanes commonly form in North-East Kansas. In particular, to take the border into account, the grid just contains the entries of the lower triangle of the whole grid. An "H" represents a hurricane usually forms in this area and a "." meansmhurricanes avoid this area. The only input is the size of the grid we want patterns for. def radar(n=5): for i in range(n): for j in range(i): if (i + j) % 2 == 0: print("H", end = "") else: print(".", end = "") print() # default end is "\n" 2. The rst line of output from radar() corresponds to which string? A. "\n" B. ".\n" C. "H\n" D. ".H\n" 3. What characters appear on the top diagonal of the shape printed by radar(5)? (ignore lines that are just white space) A. 4 periods B. 4 H's C. 2 periods and 2 H's 4. What characters (ignoring whitespace) would be printed by radar() in the rst column if the programmer had forgotton the parantheses in the condition in the radar function so that that line instead looked like this: if i + j % 2 == 0: A. 4 periods B. 4 H's C. 2 periods and 2 H's

2. A. "\n". 3. A. 4 periods 4. A. 4 periods

22. What will counts contain? Read the code carefully! Note: This question has an intentional semantic error. counts = {} # Line 1 for item in airbnb: # Line 2 reviews = item["reviews"] # Line 3 for review in reviews: # Line 4 if review not in counts: # Line 5 counts[review] = 0 # Line 6semantic error else: # Line 7 counts[review] += 1 # Line 8 A. f"": 0, "*": 0, "**": 0, "***": 0g B. f"": 1, "*": 1, "**": 2, "***": 2g C. f"**": 2, "***": 2, "": 1, "*": 1g D. f"": 1, "*": 2, "**": 3, "***": 4g E. f"": 2, "*": 2, "**": 3, "***": 3g 23. How should line 6 be modi ed to x the semantic error? A. counts[review] += 0 B. counts[review] += 1 C. counts[review] = [] D. counts.append(review) E. counts[review] = 1

22. B. {"": 1, "*": 1, "**": 2, "***": 2} 23. E. counts[review] = 1

For each question in this section, assume that the initial code executed is as follows: from collections import namedtuple Student = namedtuple("Student", ["name", "grade", "ID"]) roster = [ Student("Michael", "B", 2), Student("Sofia", "A", 3), Student(ID = 6, name = "Alexander", grade = "AB"), S tudent("Jill", "AB", 18) ] 24. What does roster[2].ID evaluate to? A. 6 B. "6" C. "B" D. 3 E. "3" 25. What is the output of the following code snippet? names = list() for student in roster: names.append(student.name) names.sort(key = lambda n: len(n)) print(names) A. [`Alexander', `Jill', `Michael', `Sofia'] B. [`Jill', `Sofia', `Michael', `Alexander'] C. [`Michael', `Sofia', `Alexander', `Jill'] D. [`Alexander', `Michael', `Sofia', `Jill'] 26. Which of the following will result in an error? A. roster.append(Student("Sarah", "A", 1)) B. roster[0] = Student("Alex", "AB", 4) C. roster[0].ID = 20 D. roster.extend([Student("Cindy", "AB", 5), Student("Jack", "A", 7)]) E. None of the above 27. Which of the following sorts roster by decreasing order of IDs? A. sorted(roster, key = lambda s:s.ID) B. sorted(roster, lambda s:s["ID"]) C. sorted(roster, lambda s:s["ID"], reverse = True) D. sorted(roster, key = lambda s:s.ID, reverse = True) 28. After executing the below code snippet, what does roster[1].name evaluate to? import copy new_roster1 = copy.copy(roster) new_roster2 = roster new_roster1[1] = Student("Rose", "B", 17) new_roster2[1] = Student("Emily", "A", 42) A. Emily B. Rose C. So a D. Michael 29. Which one of the following will create a list of student names with AB grade? A. fkey:value for key, value in students.items() if student.grade == "AB"g B. [student["name"] for student in roster if student.grade == "AB"] C. [student.name for student in roster if student.grade == "AB"] D. fstudent.name for student in roster if student.grade == "AB"g

24. A. 6 25. B. [`Jill', `Sofia', `Michael', `Alexander'] 26. C. roster[0].ID = 20 27. D. sorted(roster, key = lambda s:s.ID, reverse = True) 28. A. Emily 29. C. [student.name for student in roster if student.grade == "AB"]

Assume that the initial code executed is as follows: airbnb = [ {"name":"A", "room_id":837, "start_year":2021, "reviews":[""]}, {"name":"B", "room_id":389, "start_year":2021, "reviews":["*","","**"]}, {"name":"C", "room_id":108, "start_year":2021, "reviews":["***","**"]}, {"name":"D", "room_id":237, "start_year":2020, "reviews":["*"]}, {"name":"E", "room_id":278, "start_year":2020, "reviews":["***","**","***"]}, ] 24. Which of the following will sort airbnb based on descending order of length of reviews? A. sorted(airbnb, key = airbnb:len(d["reviews"]), reverse = True) B. sorted(airbnb, key = lambda d:len(d)) C. sorted(airbnb, key = lambda d:len(d["reviews"])) D. sorted(airbnb, key = lambda d:len(d["reviews"]), reverse = True) E. sorted(airbnb, key = lambda airbnb:len(item) for item in airbnb)

24. D. sorted(airbnb, key = lambda d:len(d["reviews"]), reverse = True)

For each question in this section, assume that the initial code executed is as follows: from collections import namedtuple Hurricane = namedtuple("Hurricane", ["name", "damage", "deaths", "mph"]) katrina = Hurricane(name = "Katrina", damage = "3.98B", deaths = "1836", mph = "175") baker = {"name": "Baker", "damage": "2.55M", "deaths": "38", "mph": "105"} 26. What does katrina.deaths evaluate to? A. "1836" B. 1836 C. "deaths" D. KeyError 27. Which of the two lines of code marked A and B will not execute successfully? Assume that if line A fails to execute, we comment it out and try to execute line B. some_dict = {} some_dict[katrina] = "Katrina - Category 5 hurricane" # line A some_dict[baker] = "Baker - Category 2 hurricane" # line B A. line A B. line B C. Both line A and line B D. Neither A nor B 28. What will be printed after this code runs? import copy some_list = [baker, katrina] new_list1 = copy.copy(some_list) new_list1[0]["name"] = new_list1[0]["name"].upper() new_list2 = copy.deepcopy(some_list) new_list2[0]["deaths"] = int(new_list1[0]["deaths"]) print(some_list[0]["name"], type(some_list[0]["deaths"])) A. Baker <class `str'> B. Baker <class `int'> C. BAKER <class `str'> D. BAKER <class `int'> 29. Which options sorts the hurricanes list in decreasing values of mph? katrina = Hurricane("Katrina", "3.98B", "1836", "175") sandy = Hurricane("Sandy", "2.34M", "546", "240") baker = Hurricane("Baker", "2.55M", "38", "105") hurricanes = [katrina, sandy, baker] def extract(hurricane): return -int(hurricane.mph) A. sorted(hurricanes, key = extract()) B. sorted(hurricanes, key = extract(hurricane)) C. sorted(hurricanes, key = extract) D. sorted(hurricanes, key = extract(hurricanes))

26. A. "1836" 27. B. line B 28. C. BAKER <class `str'> 29.C. sorted(hurricanes, key = extract)

For the following, assume the initial code executed is as follows (if a question contains code that modi es the objects, those changes should not be considered in other questions): import copy genres = ["g1", "g2", "g3"] movies = [ {"title": "A", "year": 17, "style": "short", "genres": ["g1"]}, {"title": "B", "year": 18, "style": "long", "genres": ["g2"]}, {"title": "C", "year": 19, "style": "short", "genres": ["g3"]}, {"title": "D", "year": 19, "style": "long", "genres": ["g1", "g2", "g3"]} ] def first_n(movies, n): while len(movies) > n: movies.pop() # by default, removes last item return movies 5. What does the following print? genres_new = genres genres.remove("g3") genres_new.remove("g1") print(genres) A. ["g1", "g2"] B. ["g1", "g2", "g3"] C. ["g2"] D. ["g2", "g3"] 6. What does the following print? Be careful! movies1 = first_n(movies, 2) movies2 = first_n(movies, 3) print(len(movies1), len(movies2)) A. 0 0 B. 2 0 C. 2 2 D. 2 3 E. 4 4 7. What does the following print? cp = copy.copy(movies) # shallow copy movies.append(0) movies[0]["year"] = 16 print(cp[0]["year"], len(cp)) A. 16 4 B. 16 5 C. 17 0 D. 17 4 E. 17 5 8. If copy.copy were replaced with copy.deepcopy in the previous question, what would the code print? A. 16 4 B. 16 5 C. 17 4 D. 17 5 E. 17 6

5. C ["g2"] 6. C. 2 2 7. A. 16 8. C. 17 4

def curses(x): if x == 0: return 1 else: return curses(x-1) * 2 def swap(lis, x, y): tmp = lis[y] lis[y] = lis[x] lis[x] = tmp def mix(a_list, x): swap(a_list, x, x-1) if x > 0: mix(a_list, x-1) 9. Which statement creates a new reference to the curses function object? A. f := curses B. f = curses C. f = curses() D. f = curses(x) E. f = curses(5) 10. What does curses(5) return? A. 1 B. 10 C. 16 D. 8 x 11. Which call causes a stack overow (meaning we create too many frames)? A. curses(0) B. curses(0.0) C. curses(1/0) D. curses(-1) E. curses(None) 12. What does my list look like after the following code? my_list = ["A", "B", "C"] mix(my_list, 2) A. [ ] B. [\A", \B", \C"] C. [\B", \A", \C"] D. [\C", \B", \A"] E. [\A", \B"]

9. B. f = curses 10. B. f = curses 11. D. curses(-1) 12. C. [\B", \A", \C"]

What does the following print? x = 1 y = 2 def f(x): x *= 2**3 return x + y w = f(x) v = f(y) print(str(3*x) + str(v) + "!") A. "318!" B. "2418!" C. "3010! D. "218!"

A. "318!"

In which format is everything a string? A. CSV B. JSON C. Excel spreadsheet

A. CSV

What is a good reason to serialize Python data structures to a JSON le instead of just using the data structures? A. Files remain after rebooting B. Files are faster C. JSON supports more types

A. Files remain after rebooting

Why is the following JSON le formatted incorrectly? { "Messi": { "Stats": [91, 93, 85], "Country": null, "Club": `PSG' } } A. Strings must be enclosed within double quotations B. null used instead of None C. List items must be strings D. Dictionary keys must be integers

A. Strings must be enclosed within double quotations

A key in a Python dict may be an integer (T/F). A. True B. False

A. True

What is the output of the following code? my_list = ["Alice", "Bob", "Evelyn"] your_list = my_list[:] my_list.append("Dennis") your_list.pop(0) print(your_list) A. ["Bob", "Evelyn"] B. ["Alice", "Bob", "Evelyn"] C. ["Bob", "Evelyn", "Dennis"] D. ["Alice", "Bob", "Evelyn", "Dennis"]

A. ["Bob", "Evelyn"]

What is printed from the following code? import copy monsters_v1 = ["Frankenstein", ["Vampire", "Mummy", "Ghost", "Werewolf"]] monsters_v2 = copy.deepcopy(monsters_v1) monsters_v1[1][0] = "Dracula" monsters_v1[0] = "Sand monster" print(monsters_v2) A. ["Frankenstein", ["Vampire", "Mummy", "Ghost", "Werewolf"]] B. ["Frankenstein", ["Dracula", "Mummy", "Ghost", "Werewolf"]] C. ["Sand monster", ["Vampire", "Mummy", "Ghost", "Werewolf"]] D. ["Sand monster", ["Dracula", "Mummy", "Ghost", "Werewolf"]]

A. ["Frankenstein", ["Vampire", "Mummy", "Ghost", "Werewolf"]]

What is the value of x after the code is run? import copy orig = [1, (2, 3)] x = orig y = copy.copy(orig) x[0] = 4 x[1] = (5, 6) print(y) A. [1, (2, 3)] B. [1, (5, 6)] C. [4, (2, 3)] D. [4, (5, 6)]

A. [1, (2, 3)]

Which of the following will sort words by the length of each word, with the longest word appearing rst? words = ["Psychology", "Bascom", "Noland", "Ingraham", "Soils"] A. sorted(words, key = len, reverse = True) B. sorted(words, key = len) C. sorted(words, key = lambda len, reverse = True) D. sorted(words, key = lambda len)

A. sorted(words, key = len, reverse = True)

Which of the following is a valid boolean in JSON? A. true B. True C. TRUE D. absolutely

A. true

What is the output of the following code? total = 0 halloween_dict = { "Candy Corn": -1, "Caramel Apples": 2, "Jack O' Lanterns": 3, "Skeletons": 10 } total += halloween_dict.pop("Candy Corn") halloween_dict.pop("Caramel Apples") total += halloween_dict.pop("Jack O' Lanterns") halloween_dict["Ghosts"] = total print(halloween_dict) A. {"Skeletons": 10, "Ghosts": 2} B. {"Skeletons": 10, "Ghosts": 4} C. {"Candy Corn": -1, "Caramel Apples": 2, "Jack O' Lanterns": 3, "Skeletons":10, "Ghosts": 2} D. {"Candy Corn": -1, "Caramel Apples": 2, "Jack O' Lanterns": 3, "Skeletons": 10, "Ghosts": 4}

A. {"Skeletons": 10, "Ghosts": 2}

Assume the file Hello.txt does not exist before running this code. What is the value of the variable data after the following code executes? f = open("Hello.txt", "w") f.write("Hello") f.close() f = open("Hello.txt", "w") f.write("Hello") f.write("World") f.close() f = open("Hello.txt", "r") data = f.read() f.close() A. "Hello" B. "HelloWorld" C. "Hello\nWorld" D. "HelloHelloHello" E. "Hello\nHello\nWorld"

B. "HelloWorld"

What will be in the file.txt file after this code runs? f = open("file.txt", "w") f.write("hi") f.close() f = open("file.txt", "w") f.write("I love") f.write("Python") f.close() A. "Python" B. "I lovePython" C. "I love Python" D. "hi\nI love\nPython"

B. "I lovePython"

Which lines of code will get executed in the following code? def b(): print("Start: B") # line 1 z = 100 / 0 # line 2 print("End: B") # line 3 def a(): print("Start: A") # line 4 try: # line 5 b() # line 6 except: # line 7 print("B failed") # line 8 print("End: A") # line 9 try: # line 10 a() # line 11 except: # line 12 print("A failed") # line 13 A. 1, 2, 3, 4, 5, 6, 9, 10, 11 B. 1, 2, 4, 5, 6, 7, 8, 9, 10, 11 C. 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 D. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13

B. 1, 2, 4, 5, 6, 7, 8, 9, 10, 11

What will be printed? Read the code carefully! buckets = {} bucket = [] for item in airbnb: start_year = item["start_year"] if start_year not in buckets: buckets[start_year] = [] buckets[start_year].append(item) print(len(buckets[2020]), len(buckets[2021])) A. 0 0 B. 2 3 C. 3 2 D. 5 0 E. 5 5

B. 2 3

What is the output? def foo(n): if n > 3: return n + foo(n - 1) return 0 print(foo(5)) A. 5 B. 9 C. 12 D. 15

B. 9

What is the output of the following code snippet? my_dict = {1: "One", 2: "Two", 3: "Four"} my_dict["Zero"] = 0 print(1 in my_dict and 0 in my_dict) A. True B. False C. None D. KeyError

B. False

What is the last line of code that is executed in the following code? def fun1(): # Line 1 print("Start: fun1") # Line 2 best = "fun1" + 2 # Line 3 print("End: fun1") # Line 4 def fun2(): # Line 5 print("Start: fun2") # Line 6 try: # Line 7 fun1() # Line 8 except: # Line 9 print("fun1 failed") # Line 10 print("End: fun2") # Line 11 try: # Line 12 fun2() # Line 13 except: # Line 14 print("fun2 failed") # Line 15 A. Line 10 B. Line 11 C. Line 14 D. Line 15

B. Line 11

What is the output of the following code? s = "Welcome to CS 220!" s = s.split(" ") print(s[2][-1]) A. o B. S C. CS D. 220! E. IndexError

B. S

What is printed from the following code? import copy monsters_v1 = ["Frankenstein", ["Vampire", "Mummy", "Ghost", "Werewolf"]] monsters_v2 = copy.copy(monsters_v1) monsters_v1[1][0] = "Dracula" monsters_v1[0] = "Sand monster" print(monsters_v2) A. ["Frankenstein", ["Vampire", "Mummy", "Ghost", "Werewolf"]] B. ["Frankenstein", ["Dracula", "Mummy", "Ghost", "Werewolf"]] C. ["Sand monster", ["Vampire", "Mummy", "Ghost", "Werewolf"]] D. ["Sand monster", ["Dracula", "Mummy", "Ghost", "Werewolf"]]

B. ["Frankenstein", ["Dracula", "Mummy", "Ghost", "Werewolf"]]

What is the default delimiter between columns in a CSV file? A. colon B. comma C. newline D. semicolon

B. comma

What will be printed after this code runs? s = "Nice day, isn't it?" words = s.split(" ") print(words.pop(-1)) A. ? B. it? C. isn't it? D. Nice E. Nice day, isn't

B. it?

Which of the following are the delimiters of the rows in a CSV le? A. space B. newline C. comma D. semicolon

B. newline

Which of the following is a valid JSON? A. {"Messi":{"Stats":'91, 93, 85', "Country":null, "Club":'PSG'}} B. {"Messi":{"Stats":"91, 93, 85", "Country":null, "Club":"PSG"}} C. {"Messi":{"Stats", [91, 93, 85], "Country", null, "Club", "PSG"}} D. {"Messi":{"Stats":[91, 93, 85], "Country":None, "Club":"PSG"}}

B. {"Messi":{"Stats":"91, 93, 85", "Country":null, "Club":"PSG"}}

What is the output of the following code snippet? s = "Hello World!" s = s.upper().split(" ") print(s[-1][-1]) A. WORLD! B. D C. ! D. IndexError

C. !

What is the output? def mystery(item_list): count = 0 for item in item_list: if type(item) == list: count += mystery(item) else: count += 1 return count print(mystery([[1, 2], 3, [4, 5, 6], 7])) A. 0 B. 4 C. 7 D. 28

C. 7

What will be in the le after this code runs? f = open("file.txt", "w") f.write("Hello") f.close() f = open("file.txt", "w") f.write("World") f.close() f = open("file.txt") data = f.read() data = "!!!!!" f.close() A. !!!!! B. Hello C. World D. HelloWorld!!!!! E. Hello World !!!!!

C. World

Which of the following will result possibly refer to? Assume Python version is 3.6 or above. result = [] for x in airbnb[1]: result.append(x) result A. ["r", "o", "o", "m", " ", "i", "d"] B. ["reviews", "start year", "room id", "name"] C. ["name", "room id", "start year", "reviews"] D. ["A", 837, 2021, [""]] E. ["A", 837, 2021, ""]

C. ["name", "room id", "start year", "reviews"]

What is the output of the following piece of code? input_data = [12, 3, 0, 2] output_data = [] for number in input_data: try: output_data.append(12 // number) except: output_data.append(-1) print(output_data) A. [1, 4] B. [1, 4, -1] C. [1, 4, -1, 6] D. [-1, 1, -1, -1] E. ZeroDivisionError Page

C. [1, 4, -1, 6]

What will the following code print? a = [1] b = [2, 3] c = [6, 7] b = c c.pop(-1) b.append(a[-1]) print(a, b) A. [1] [2, 3] B. [1] [2, 3, 1] C. [1] [6, 1] D. [1] [6, 7, 1] E. [2, 3] [6, 1]

C. [1] [6, 1]

Which of the following is mutable? A. tuple B. string C. dictionary D. int

C. dictionary

What is the output of the following code? msg = "Hey220" msg.upper() for i in range(len(msg)): if msg[i].isdigit(): print(msg[i - 2]) break A. 2 B. E C. e D. Hey220 E. HEY220

C. e

What call to foo will not cause an AssertionError? def foo(word1, word2): assert type(word1) == str and type(word2) == str assert len(word1) < len(word2) return (word1 + " is better than " + word2) A. foo("penguin", "bear") B. foo(["seal"], "koala") C. foo("tiger", "elephant") D. foo("wolf", "frog") E. foo("zebra", ["pig"])

C. foo("tiger", "elephant")

Suppose double check exam.txt has the following content: Wisc ID number bubbled in Special code matches exam Answers filled in completely What is the output of the below code snippet? f = open("double_check_exam.txt") for line in f: print(line[1]) f.close() A. Wisc ID B. Special code matches exam C. i p n D. ID code filled E. Wi Sp An

C. i p n

Which of the following will correctly sort players by jersey number? players = [{"name":"Alia", "jersey":17,"age":20}, {"name":"Brianna", "jersey":6, "age":19}, {"name":"Carl", "jersey":10, "age":21} ] A. sorted(players, key = jersey) B. sorted(players.items(), key = jersey) C. sorted(players, key = lambda p:p["jersey"]) D. sorted(players.items(), key = lambda p:p["jersey"])

C. sorted(players, key = lambda p:p["jersey"])

Which of the following will access Jenny's math grade? student = {} student["name"] = "Jenny" student["grades"] = {"math": 90, "biology": 95} A. grades["math"] B. grades["Jenny"]["math"] C. student["grades"]["math"] D. student["Jenny"]["math"]

C. student["grades"]["math"]

What is the output of the following code? Assume Python version is 3.6 or above. d = {1: "one", 2: "two", 3: "three"} d[0] = "zero" d2 = dict() for k in d: d2[d[k]] = k print(len(d2), list(d2.keys())[0]) A. 4 0 B. 4 1 C. 4 zero D. 4 one

D. 4 one

What values are printed by the code below? def f(n): if n > 5: f(n-1) print(n, end=" ") f(9) A. 9 8 7 6 B. 9 8 7 6 5 C. 5 6 7 8 D. 5 6 7 8 9 E. The program runs into a RecursionError

D. 5 6 7 8 9

What is the output of the following piece of code? Assume that the code does not crash due to exceptions. Also, assume that some file.txt contains the following content. I promise to always close my files f = open(`some_file.txt') data = f.read() lines = data.split(`\n') print(type(data), type(lines)) A. <class `list'> <class `list'> B. class `str'> <class `str'> C. <class `list'> <class `str'> D. <class `str'> <class `list'>

D. <class `str'> <class `list'>

What is the final value of letter list and number list after the following code is executed? letter_list = ["B", "D", "E", "A", "C"] letter_list = letter_list.sort(reverse = True) number_list = [10, 50, 40, 20, 30] number_list = sorted(number_list, reverse = True) print(letter_list, number_list) A. ["E", "D", "C", "B", "A"] [50, 40, 30, 20, 10] B. ["B", "D", "E", "A", "C"] None C. ["E", "D", "C", "B", "A"] [10, 50, 40, 20, 30] D. None [50, 40, 30, 20, 10] E. None None

D. None [50, 40, 30, 20, 10]

What will be printed after this code runs? a = [1] b = [2] c = b c.append(1) c.sort() a.append(b) print(a, b) A. [1, [2]] [2] B. [1, 1, 2] [1, 2] C. [1] [1, 2] D. [1, [1, 2]] [1, 2] E. [1, [2]] [2]

D. [1, [1, 2]] [1, 2]

Consider the following code. What is the value of list1 after the following code executes? list1 = [] list2 = [2, 1, 0, 4, 5] i = 0 while i <= len(list2): try: c = 10 + list2[i] list1.append(c) except: list1.append(0) i += 1 A. [0, 0, 0, 0, 0] B. [2, 1, 0, 4, 5] C. [12, 11, 10, 14, 15] D. [12, 11, 10, 14, 15, 0] E. The program runs into a IndexError

D. [12, 11, 10, 14, 15, 0]

Which of the following would generate a case-insensitive list of words containing "s"? lattes = ["Pumpkin Spice", "Coconut", "Pistachio", "Vanilla"] A. [for latte in lattes: if "s" in latte.lower(): latte] B. [latte if "s" in latte.lower() for latte in lattes] C. [latte for latte in lattes if "s" in latte] D. [latte for latte in lattes if "s" in latte.lower()] E. [latte for latte in lattes if "s" in latte.upper()]

D. [latte for latte in lattes if "s" in latte.lower()]

Which of the following will generate a list of words with a length longer than 7? words = ["Psychology", "Bascom", "Noland", "Ingraham", "Soils"] A. [len(w) for w in words if len(w) > 7] B. [len(words) for w in words if len(words) > 7] C. [words for w in words if len(words) > 7] D. [w for w in words if len(w) > 7]

D. [w for w in words if len(w) > 7]

Which of the following is not a sequence? A. tuple B. list C. string D. dictionary

D. dictionary

What call to foo will not cause an AssertionError? def foo(a, b): assert type(a) == int and type(b) == int assert a % 2 == 1 and a < b return a + b A. foo(12.0, 7.0) B. foo(17, 11) C. foo(12, 17) D. foo(11, 17) E. foo(12, 17.0)

D. foo(11, 17)

What line is printed last when the following code is executed? my_list = [2, 0, 5, 0] for item in my_list: try: print ("The number is:", item) amount = 1 / item print(amount) except ZeroDivisionError as e: print("help!") A. The number is: 0 B. The number is: 5 C. ZeroDivisionError D. help!

D. help!

Rows of a CSV are normally delimited by which of the following? A. commas B. semicolons C. quotes D. new lines

D. new lines

What is the output of the following code? colors_dict = {"Red": 25, "Orange": 23, "Yellow": 32, "Brown": 7} colors_dict[0] = "Green" print(colors_dict[23]) A. "Red" B. 25 C. "Orange" D. 23 E. KeyError

E. KeyError

What is the output of the following code? a = (1, 2, 3) a[0] = a[1] + a[2] print(a[1]) A. 1 B. 2 C. 3 D. 5 E. Nothing because the program crashes

E. Nothing because the program crashes

What line is printed last when the following code is run? my_list = [1.1, 0.3, 0.6] for element in my_list: try: print("The element is:", element) reciprocal = 1 // int(element) print(reciprocal) except ZeroDivisionError as e: print("Oops!!!") A. The element is: 0.6 B. The element is: 0.3 C. The element is: 1.1 D. ZeroDivisionError E. Oops!!!

E. Oops!!!

Which of the following will produce a sorted dictionary based on the score of the players ordered from highest to lowest? player_scores = {"Alice": 20, "Bob": 25, "Caroline": 21} A. player scores.sort(reverse = True) B. sorted(player scores.items(), key = key[1], reverse = True) C. player scores.sort(key = key[1]) D. dict(sorted(player scores.items(), key = lambda k:k[0], reverse = True)) E. dict(sorted(player scores.items(), key = lambda k:k[1], reverse = True))

E. dict(sorted(player scores.items(), key = lambda k:k[1], reverse = True))

What is the output of the following code? a = ([10], 30) b = a c = b[0] c.append(20) b = b + (40, 50) print(a) a. ([10, 20], 30) b. ([10, 20], 30, 40, 50) c. ([10], 30, 40, 50) d. ([10], 30)

a. ([10, 20], 30)

What will be printed and in what order? def square_numbers(nums): for i in nums: yield (i*i) my_nums = square_numbers([1,2,3,4,5]) for num in my_nums: print(num) a. 1, 4, 9, 16, 25 b. <generator object square_numbers at 0x10c3877c8> c. 1 d. 25

a. 1, 4, 9, 16, 25

What does the following code print? def foo(input_object): for item in input_object item = item + 1 return sum(input_object) num_list = [1,2,3] print(foo(num_list)) a. 6 b. 9 c. [1, 2, 3] d. [2, 3, 4]

a. 6

What lines of code execute in the following? a = 1 # line 1 b = 0 # line 2 c = a/b # line 3 try: print("a/b is " + str(c)) # line 4 except: print("Got a divide-by-zero error!") # line 5 print("exiting") # line 6 a. Lines 1, 2, and 3 b. Lines 1, 2, 3, and 4 c. Lines 1, 2, 3, and 5 d. Lines 1, 2, 3, and 6 e. Lines 1, 2, 3, 4, 5, and 6

a. Lines 1, 2, and 3

What does the following evaluate to? "UID12345"[3:].lower().isdigit() a. True b. False c. 12345 d. D12345 e. None

a. True

What is the value of x after this code is run? orig = [1,[2, 3]] x = orig y = copy.deepcopy(orig) y[0] = 4 y[1][0] = 5 y[1][1] = 6 print(x) a. [1, [2, 3]] b. [4, [2, 3]] c. [4, [5, 6]] d. [1, [5, 6]]

a. [1, [2, 3]]

Consider the following code: movies = [ {"name": "m1", "actors": ["A", "B"], "genres": ["X"]}, {"name": "m2", "actors": ["C", "D"], "genres": ["X", "Y"]}, {"name": "m3", "actors": ["A", "C"], "genres": ["Y", "Z"]}, {"name": "m4", "actors": ["B", "C"], "genres": ["X", "Z"]}, ] # key: actor name, val: list of unique genres actor has acted in actor_genres = {} for movie in movies: for actor in movie["actors"]: for genre in movie["genres"]: if not actor in actor_genres: _____________________ <what goes here? if not genre in actor_genres[actor]: actor_genres[actor].append(genre) What should be inserted to populate actor_genres as described in the comment? (your code should not result in movies being changed). a. actor_genres[actor] = [] b. actor_genres[actor] = {} c. actor_genres[actor] = movie["genres"] d. actor_genres[genre] = [] e. pass

a. actor_genres[actor] = []

What is the type of data and lines in the following code? f = open("file.txt") data = f.read() lines = data.split('\n') a. data is a string and lines is a list b. data is a list and lines is a string c. both data and lines are lists d. both data and lines are strings

a. data is a string and lines is a list

What will be printed and in what order? nums = [1, 2, 3] words = ["one", "two", "three"] print(words[nums.index(2)]) words = ["zero"] + words nums = [0] + nums print(words[nums.index(2)]) a. two, two b. two, one c. one, two d. two, three

a. two, two

Using which command in a function body makes the function a generator function? a. yield b. return c. generate d. next

a. yield

What is the output of the following code? words = ["one", "two", "three", "four", "five"] d = {} for word in words: if len(word) not in d: d[len(word)] = [word] else: d[len(word)] += [word] print(d) a. {3: ['one', 'two'], 5: ['three'], 4: ['four', 'five']} b. {1: 'one', 2: 'two', 3: 'three', 4: 'four', 5: 'five'} c. {'one': 3, 'two': 3, 'three': 5, 'four': 4, 'five': 4} d. {3: ['two'], 5: ['three'], 4: ['five']}

a. {3: ['one', 'two'], 5: ['three'], 4: ['four', 'five']}

Which of the following is True? a. "bcd" < "abc" b. "BCD" < "abc" c. "bcd" < "ABC" d. "abbc" < "abb" e. "A2" < "A11"

b. "BCD" < "abc"

What does the following code print? def foo(obj_a, obj_B): return obj_a + obj_b y = foo a = 1 b = 2 c = 3 print(y(a,b) + y(b,c)) a. 6 b. 8 c. 35 d. Code generates TypeError e. Code prints representation of foo

b. 8

What is printed? data = {1: {"f": "Alice"}, 2: {"f": "Bob", "l": "Smith"}} print(data[1]["f"], data[1].get("l", "Doe")) a. Alice b. Alice Doe c. Alice Smith d. Bob Doe e. Bob Smith

b. Alice Doe

A key in a JSON dict may be an integer (T/F). A. True B. False

b. False

Just like infinite iteration, infinite recursion make a program run forever a. True b. False

b. False

What is the value in my_list after this code is run? my_list = ["Alice", "Bob", "Charlie", "Dennis"] your_list = my_list my_list.remove("Alice") your_list.remove("Dennis") print(my_list) a. ["Bob", "Charlie", "Dennis"] b. ["Bob", "Charlie"] c. ["Alice", "Bob","Charlie", "Dennis"] d. ["Alice", "Bob","Charlie"]

b. ["Bob", "Charlie"]

What does the following code print? before = [10, 20] after = [] for i in range(3): try: after.append(before[i]) except: after.append(1) print(after) a. [10, 20] b. [10, 20, -1] c. [10, 20, -1,-1] d. [10, 20, 20] e. [20, -1,-1]

b. [10, 20, -1]

What will be printed and in what order? d1 = {1 : "one", 2 : "two", 3 : "three"} d1[0] = "zero" d2 = dict() for k in d1: d2[d1[k]] = k print(d1[3]) print(d2["three"]) a. three, KeyError b. three, 3 c. 3, three d. KeyError, 3

b. three, 3

What is the output of the following code? def foo(x): return x % 2 == 1 def special_sum(nums, check): total = 0 for num in nums: if check(num): total += num return total print(special_sum([1, 3, 4, 9], foo)) a. 1 b. 4 c. 13 d. 17 e. None

c. 13

What will be printed and in what order? nums = [10, 20, 30, 40, 50] print(nums[1]) print(nums[1:3]) a. 40 and [20, 30] b. 50 and [20, 30, 40] c. 50 and [20, 30] d. IndexError: list index out of range

c. 50 and [20, 30]

What does the following code print? s = "this is a test" words = s.split(" ") words[3] = "?" * len(words[1]) print(" ".join(words)) a. This is a test b. This is ???? test c. This is a ???? d. This is a ? e. None of the above because an IndexError occurs

c. This is a ????

Which of the following cannot be used as a key for a Python dictionary? a. tuples b. namedtuples c. lists d. strings e. negative integers

c. lists

What is printed? data = [["A", "B", "C"], [1,2,3], [4,5,6], [7,8,9]] idx = data[0].index("B") total = 0 for row in data[1:]: total += row[idx] print(total) a. 6 b. 12 c. 13 d. 15 e. 24

d. 15

What does ternary(7) return? def ternary(n): if n < 3: return str(n) else: quo = n // 3 rem = n % 3 return ternary(quo) + ternary(rem) a. 3 b. 7 c. 12 d. 21 e. None of the above because there is a stack overflow

d. 21

Which of the following statements are true? a. When you open a file for reading, if the file does not exist, an error occurs b. When you open a file with mode "w", if the file does not exist, a new file is created c. When you open a file with mode "w", if the file exists, the existing file is overwritten with the new file d. All of the above

d. All of the above

What does f("ABC") return? def f(text): if len(text) <= 1: return text return f(text[1:]) + text[0] a. A b. C c. ABC d. CBA e. None of the above because there is a stack overflow

d. CBA

What is the output of the following code? my_list = ["movies", "friends", "family", "books"] my_list.append("music") my_list.pop(3) my_list.sort() print(my_list) a. ['books', 'family', 'friends', 'movies',] b. ['books', 'family', 'friends', 'movies', 'music'] c. ['movies', 'friends', 'family', 'books', 'music'] d. ['family', 'friends', 'movies', 'music']

d. ['family', 'friends', 'movies', 'music']