Iteration using range() in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of range() with step

What is the output of this Python code?

result = []
for i in range(2, 10, 3):
    result.append(i)
print(result)

Python

result = []
for i in range(2, 10, 3):
    result.append(i)
print(result)

A [2, 6, 9]

B [2, 5, 8]

C [2, 3, 4, 5, 6, 7, 8, 9]

D [3, 6, 9]

💡 Hint

Remember that range(start, stop, step) includes start but excludes stop.

range(2, 10, 3) starts at 2 and adds 3 each time until it reaches or passes 10. So it produces 2, 5, 8.

❓ Predict Output

intermediate

Counting iterations with negative step

What will be printed by this code?

count = 0
for x in range(10, 0, -2):
    count += 1
print(count)

Python

count = 0
for x in range(10, 0, -2):
    count += 1
print(count)

A 5

B 6

C 0

D 4

💡 Hint

Count how many numbers are generated from 10 down to 1 stepping by -2.

range(10, 0, -2) generates 10, 8, 6, 4, 2. That's 5 numbers, so count is 5.

🧠 Conceptual

advanced

Behavior of range() with equal start and stop

What does list(range(5, 5)) produce in Python?

A Raises ValueError

B [5]

C [0, 1, 2, 3, 4]

D []

💡 Hint

Think about whether the stop value is included or excluded.

range(start, stop) includes start but excludes stop. If start == stop, no numbers are generated.

❓ Predict Output

advanced

Output of nested loops with range()

What is the output of this code?

result = []
for i in range(1, 4):
    for j in range(i):
        result.append(j)
print(result)

Python

result = []
for i in range(1, 4):
    for j in range(i):
        result.append(j)
print(result)

A [0, 1, 0, 1, 2]

B [1, 2, 3]

C [0, 0, 1, 0, 1, 2]

D [0, 1, 2]

💡 Hint

Look at how many times the inner loop runs for each outer loop iteration.

For i=1, j runs 0; for i=2, j runs 0,1; for i=3, j runs 0,1,2. All appended in order.

🔧 Debug

expert

Identify the error in this range usage

What error does this code raise?

for i in range(5, 1, 1):
    print(i)

Python

for i in range(5, 1, 1):
    print(i)

A Prints nothing

B Prints 5, 6, 7, 8, 9

C Raises ValueError

D Infinite loop

💡 Hint

Check if the step direction matches the start and stop values.

range(5, 1, 1) tries to count up from 5 to 1 but 1 is less than 5, so no values are generated.