Basic Python: Practice Questions

For each snippet, write the output. If it prints nothing, write “No Output”.

Basic Math

You are responsible for all of the basic math operators and understanding how order of operations works. The quizzes will only test integer math that you should be able to complete easily with paper and pencil.

Question 1

x = 2 // 3
y = x * 4 
z = y + 5 
print("z=", z)

Answer

z= 5

Question 2

x = 3 // 2
y = x % 4
z = y - 5
print("z=", z)

Answer

z= -4

Question 3

x = 3 // 2 # 4
y = x % 4
z = y - 5 # 2 - 1
print("z=", z)

Answer

z= -4

Question 4

print(2 * 2 ** 2 + 3 * 4 % 2)

Answer

8

Question 5

print(2 ** 2 * 2 // 3 - 4 + 2)

Answer

0

if statements

You are responsible for understanding basic boolean operations (and, or, not) and comparison operators (>=, >, <, <=, ==).

Question 6

x = 4%5
y = 4//5
if x == 1 or y == 1:
    result = 0
else:
    result = 1
print('result=', result)

Answer

result= 1

Question 7

x = 4-5
y = 5-4
if x == 1 and y == 1:
    result = 0
else:
    result = 1
print('result=', result)

Answer

result= 1

In python, it is common to rely on “truthy” and “falsey” values rather than only the boolean values True and False.

Question 8

if '':
    result = 0
else:
    result = 1
print('result=', result)

Answer

result= 1

Question 9

if 1.0:
    result = 0
else:
    result = 1
print('result=', result)

Answer

result= 0

Loops

You are responsible for understanding how while loops behave.

Question 10

i = 0
total = 0
while i < 5:
    total = total + i
    i += 1
print('total=', total)

Answer

total= 10

Question 11

i = 3
total = 0
while i < 8:
    total = total * i
    i += 1
print('total=', total)

Answer

total= 0

Question 12

i = 34567
total = 0
while i > 0:
    total += 1
    i //= 10
print('total=', total)

Answer

total= 5

Truthy/falsey values commonly are used within the condition of while loops in python, not just for if statements.

Question 13

i = 123
total = 0
while i:
    total += 1
    i //= 10
print('total=', total)

Answer

total= 3

For loops are much more common in python (and most other programming languages) because they are easier to reason about. Everything that a for loop can do, a while loop can also do. But a while loop can do things that for loops can’t (like loop forever). It is considered good style to use for loops whenever possible. The hardest part about for loops is understanding the range function, which is commonly used with for loops.

Question 14

total = 0
for i in range(5):
    total = total - 1
print('total=', total)

Answer

total= -5

Question 15

total = 0
for i in range(3, 5):
    total = total + 1
print('total=', total)

Answer

total= 2

Question 16

total = 42
for i in range(10, 15, 1):
    total %= i
print("total=", total)

Answer

total= 2

Question 17

total = 0
for i in range(10, 0, -2):
    total -= i
print("total=", total)

Answer

total= -30

Nested for loops are very common with lists. You will need to implement many nested loops in this class, and you can expect a problem with nested loops on almost every quiz for the remainder of the course.

Question 18

result = 1
for i in range(5):
    if i<3:
        result *= 1
    else:
        result *= (-1)
print('result=', result)

Answer

result= 1

Question 19

result = 1
for i in range(3, 5):
    if i<3:
        result += 1
    else:
        result -= 1
print('result=', result)

Answer

result= -1

Question 20

result = 1
for i in range(5):
    if i <= 3:
        result += i
    else:
        result += 1
print('result=', result)

Answer

result= 8

Question 21

result = 1
for i in range(5):
    if i > 3:
        result += i
    else:
        result += 1
print('result=', result)

Answer

result= 9

Question 22

total = 0
for i in range(10, 20, 5):
    if i%2 == 1 or i<15:
        total += i
print("total=", total)

Answer

total= 25

Question 23

total = 0
for i in range(0, 10, 3):
    if i%2 == 0 or i<5:
        total += i
print("total=", total)

Answer

total= 9

Lists

A list is the most basic container type in python. For this quiz, you are responsible for how to read from a list, but not how to modify a list. You are responsible for the functions sum, min, and max; you are also responsible for understanding list slices and list indexing.

Question 24

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21] 
total = 0 
total += xs[0]
total += xs[1]
total += xs[-3]
print('total=', total)

Answer

total= 21

Question 25

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
total = 0
total += xs[3]
total += xs[-1]
total += xs[0]
print('total=', total)

Answer

total= 29

Question 26

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
total = 0
total += xs[5]
total += xs[-5]
total += xs[-4]
print('total=', total)

Answer

total= 39

Question 27

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[3:5]
total = 0
total += ys[0]
total += ys[1]
total += ys[-1]
print('total=', total)

Answer

total= 25

Question 28

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-5:-3]
total = 0
total += ys[0]
total += ys[1]
total += ys[-1]
print('total=', total)

Answer

total= 43

Question 29

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-5:-3]
total = len(ys)
print('total=', total)

Answer

total= 2

Question 30

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-5:-3]
total = sum(ys)
print('total=', total)

Answer

total= 28

Question 31

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-3:-5]
total = sum(ys)
print('total=', total)

Answer

total= 0

Question 32

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-3:-5:-1]
total = sum(ys)
print('total=', total)

Answer

total= 32

Question 33

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[:3]
total = sum(ys)
print('total=', total)

Answer

total= 9

Question 34

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[:3]
total = min(ys)
print('total=', total)

Answer

total= 1

Question 35

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[:3]
total = max(ys)
print('total=', total)

Answer

total= 5

Question 36

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[7:]
total = sum(ys)
print('total=', total)

Answer

total= 72

Question 37

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
ys = xs[-3:]
total = sum(ys)
print('total=', total)

Answer

total= 57

In practice, lists are almost always combined with for loops.

Question 38

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
total = 0
for i in range(3):
    total += xs[i]
print('total=', total)

Answer

total= 9

Question 39

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
total = 0
for i in range(3, 8, 2):
    total += xs[i]
print('total=', total)

Answer

total= 33

Question 40

xs = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21]
total = 0
for i in range(-3, -6, -1):
    total += xs[i]
print('total=', total)

Answer

total= 45

Question 41

xs = [1, 3, 5]
total = 0
for x in xs:
    total += x
print('total=', total)

Answer

total= 9

Question 42

xs = [1, 3, 5]
total = 0
for x in xs:
    for i in range(3):
        total += x*i
print('total=', total)

Answer

total= 27

Question 43

xs = [1, 3, 5]
ys = [2, 4, 6]
total = 0
for x in xs:
    total += x
    for y in ys:
        total -= x*y
print('total=', total)

Answer

total= -99

Question 44

xss = [[1, 3, 5], [2, 4], [0, 1, 2, 3, 4, 5]]
total = 0
total += xss[0][0]
total += xss[1][1]
total += xss[2][2]
print('total=', total)

Answer

total= 7

Question 45

xss = [[1, 3, 5], [2, 4], [0, 1, 2, 3, 4, 5]]
total = 0
total += xss[1][0]
total += xss[0][1]
total += xss[0][2]
print('total=', total)

Answer

total= 10

Question 46

xss = [[1, 3, 5], [2, 4], [0, 1, 2, 3, 4, 5]]
total = 0
for xs in xss:
    total += xs[0]
    for x in xs:
        total += x
print('total=', total)

Answer

total= 33

Question 47

xss = [[1, 3, 5], [2, 4], [0, 1, 2, 3, 4, 5]]
total = 0
for i in range(2):
    for j in range(len(xss[i])):
        total += xss[i][-j]
print('total=', total)

Answer

total= 15

Question 48

xss = [[1, 3, 5], [2, 4], [0, 1, 2, 3, 4, 5]]
total = 0
for i in range(len(xss)):
    for j in range(i + 1):
        total += xss[i][j]
print('total=', total)

Answer

total= 10

Functions

Functions allow you to reuse the same piece of code many times. A common acronym for good programming is DRY (don’t repeat yourself), and so functions are used all the time. Like nested for loops, expect many problems in future quizzes to involve functions.

Question 49

x = 10
def foo(x):
    if x - 5:
        return 1
    else:
        x += 1
    return x
x += foo(4)
x += foo(5)
x += foo(6)
print("x=", x)

Answer

x= 18

Question 50

x = 10
def foo(x):
    x += 2
    return x
x += foo(9 + 39 // 10) * 3
x += foo(9 + 19 // 10) * 2
print("x=", x)

Answer

x= 76

Question 51

x = 10
def foo(x):
    if x % 2:
        return 1
    x -= 1
    return x
x += foo(4)
x += foo(5)
x += foo(6)
print("x=", x)

Answer

x= 19

Question 52

x = 10
def foo(x):
    x += 1
    return x
x += foo(9 + 39 // 10) * 2
print("x=", x)

Answer

x= 36

Question 53

x = 10
def foo(x):
    return x * 2
for i in range(3):
    x += foo(i)
print("x=", x)

Answer

x= 16

Question 54

x = 10
def foo(x):
    if x - 5:
        return 1
    else:
        x -= 1
    return x
x += foo(4)
x += foo(5)
x += foo(6)
print("x=", x)

Answer

x= 16

Question 55

x = 10
def foo(x):
    x += 2
    return x
x += foo(9 + 39 // 10) * 3
x += foo(9 + 39 // 10) * 2
print("x=", x)

Answer

x= 80

Question 56

def foo(x):
    total = 0
    while x > 0:
        total += 1
        x //= 10
    return total
x = foo(100)
x += foo(1234567)
x += foo(3)
print("x=", x)

Answer

x= 11

Question 57

def foo(x):
    total = 0
    while x > 0:
        total = total + x % 10
        x //= 10
    return total
x = foo(100)
x += foo(1234567)
x += foo(3)
print("x=", x)

Answer

x= 32