Unit 4: Functions and recursion - Practice Quiz

1 Which symbol is used to call a Python function?

2 What is the output of print("Hello")?

3 Which statement correctly calls a function named greet?

4 What is the result of int("8")?

5 What is the result of float(5)?

6 What is the value of 3 + 2.5 in Python?

7 Which function converts a number into a string?

8 Which module provides many mathematical functions in Python?

9 What does math.sqrt(25) return?

10 What does the function abs(-7) return?

11 Which statement imports the math module?

12 Which keyword begins a function definition in Python?

13 Which function definition is syntactically correct?

14 What keyword sends a value back from a function?

15 What is the main purpose of creating a function?

16 In def greet(name):, what is name?

17 In greet("Ana"), what is "Ana"?

18 What does a function parameter store?

19 What is recursion?

20 What does a recursive function need to stop calling itself?

21 What is printed by the following code?

print(round(abs(-4.67), 1))

22 Given the function below, what is the value of result?

def combine(a, b):
    return a * 2 + b

result = combine(combine(2, 1), 3)

23 What happens when this code is executed?

def announce():
    print("Ready")

value = announce()
print(value)

24 What is the value and type of result after this statement?

result = int("12") + float("3.5")

25 Which expression evaluates to the string "Age: 21" when age = 21?

26 What is printed by the following code?

x = 7
y = 2
print(float(x // y))

27 Which statement about the expression True + 4.5 is correct in Python?

28 Assuming import math has been executed, which expression calculates the length of the hypotenuse for legs a and b?

29 What is printed by the following code?

import math
print(math.ceil(3.2) + math.floor(3.8))

30 A program stores an angle as 60 degrees. Which expression correctly computes its sine?

31 Which function correctly returns the average of three numbers?

32 What is printed by this program?

def adjust(n):
    n = n + 5
    return n

value = 10
adjust(value)
print(value)

33 A function should return True only when a number is divisible by both 3 and 5. Which definition is correct?

34 What is printed by the following code?

def describe(name, score=0):
    print(name, score)

describe("Mira", 8)
describe("Leo")

35 Given def power(base, exponent): return base ** exponent, which call computes using keyword arguments?

36 What is the result of the following call?

def calculate(x, y=2, z=3):
    return x + y * z

calculate(4, z=5)

37 What happens when greet("Ana", message="Hi") is called for the function below?

def greet(message, name):
    return message + ", " + name

38 What value is returned by total(4)?

def total(n):
    if n == 0:
        return 0
    return n + total(n - 1)

39 What is the main problem with this recursive function when called with a positive integer?

def countdown(n):
    print(n)
    return countdown(n - 1)

40 What is returned by mystery(13)?

def mystery(n):
    if n < 10:
        return n
    return mystery(n // 10) + n % 10

41 What is printed by the following code?

def maker():
    print("M", end="")
    return lambda x, y: x - y

def value(n):
    print(n, end="")
    return n

print(maker()(value(7), value(2)))

42 What is printed by the following code?

def emit(x):
    print(x, end="")
    return x

def combine(a, b, c):
    return a + b + c

print(combine(emit(1), *(emit(2),), c=emit(3)))

43 What is the output of this Python 3 expression?

print((int(-3.9), round(2.5), round(3.5), int("11", 2)))

44 What is printed by the following code?

print((bool("0"), bool(0.0), int(True), str(False)))

45 What is the output of the following mixed-type operations?

print((5 // 2.0, 5 % 2.0, True + 2, 2 ** -1))

46 What happens when this Python 3 program is executed?

results = []
for text in ["101", "0b101", "010"]:
    results.append(int(text, 0))
print(results)

47 Using the default tolerances, what is printed?

import math

print((
    math.isclose(1_000_000_000, 1_000_000_001),
    math.isclose(0.0, 1e-10)
))

48 Assuming standard Python binary floating-point arithmetic, what is printed?

import math

naive = (1e16 + 1.0) - 1e16
accurate = math.fsum([1e16, 1.0, -1e16])
print((naive, accurate))

49 What is the output of the following code?

import math

x = -2.7
print((math.floor(x), math.ceil(x), math.trunc(x)))

50 What happens when this annotated function is called?

def repeat(text: str, count: int) -> str:
    return text * count

print(repeat(3, "ab"))

51 What is printed by the following program?

def f():
    return g() + 1

def g():
    return 10

h = f

def g():
    return 20

print(h())

52 What happens when adjust() is called?

x = 10

def adjust():
    print(x)
    x = 20

adjust()

53 Given the function below, which call executes without TypeError and returns 19?

def score(a, b=2, /, c=3, *, d=4):
    return a + b + c + d

54 What happens in the following call?

def configure(a, b=0, **extra):
    return a, b, extra

values = {"b": 2, "c": 3}
print(configure(1, b=4, **values))

55 What is printed by this program?

def collect(x, items=[]):
    items.append(x)
    return tuple(items)

print(collect(1), collect(2), collect(3, []), collect(4))

56 What is printed after the following function call?

def update(a, b):
    a += [9]
    b = b + [8]

data = []
update(data, data)
print(data)

57 What value is printed by this recursive function?

def f(n):
    if n == 0:
        return 1
    return n - f(n - 1)

print(f(4))

58 What is printed by the following recursive traversal?

def trace(n):
    if n == 0:
        return
    print(n, end="")
    trace(n - 1)
    print(n, end="")

trace(3)

59 Including the initial call, how many total invocations of counted(5) and its recursive descendants occur?

def counted(n):
    if n <= 1:
        return 1
    return counted(n - 1) + counted(n - 2)

counted(5)

60 Consider a recursive binary search that makes exactly one recursive call on half of the remaining sorted array. For an absent target among distinct elements, what are its worst-case time complexity and auxiliary call-stack space?