Python coding practice for beginners

Practice by writing a small program, checking its output, then testing a boundary case. These five exercises cover variables, conditions, collections and functions. You can use the free PyNex Python compiler without installing Python.

How to use these exercises

Open the compiler in another tab and write your own solution first.
Run it and compare the printed result with the expected output.
Try every boundary test before opening the reference solution.
Explain why the solution works, then change the inputs and run it again.

1. Add an order total

A notebook costs ₹45 and a pen costs ₹12. Buy two notebooks and three pens. Calculate the total using variables, then print the number.

Expected printed output

Check your solution: Change the notebook quantity to 3. The total should become 171.

Common mistake: Use numbers for calculation. Quoted values such as "45" are strings.

Show reference solution

notebook = 45
pen = 12
total = 2 * notebook + 3 * pen
print(total)

2. Choose a delivery fee

Set order_total to 450. Delivery is free for orders of 500 or more, otherwise it costs 40. Print the delivery fee.

Expected printed output

Check your solution: Test 499, 500 and 501. Expected fees: 40, 0 and 0.

Common mistake: The boundary includes 500, so use >= rather than >.

Show reference solution

order_total = 450
if order_total >= 500:
    delivery = 0
else:
    delivery = 40
print(delivery)

3. Filter passing scores

Given scores = [42, 75, 60, 35, 90], create a list containing scores of at least 60. Keep the original order.

Expected printed output

[75, 60, 90]

Check your solution: An empty input list should produce []. A score of exactly 60 must be included.

Common mistake: Do not remove items from the list while iterating over it. Build a new list.

Show reference solution

scores = [42, 75, 60, 35, 90]
passing = []
for score in scores:
    if score >= 60:
        passing.append(score)
print(passing)

4. Count repeated words

Count words in ["python", "ai", "python", "data", "ai"]. Return a dictionary mapping each word to its count.

Expected printed output

{'python': 2, 'ai': 2, 'data': 1}

Check your solution: Test an empty list and three copies of the same word. Dictionary key order does not affect the counts.

Common mistake: Initialize a missing key before incrementing it; get(word, 0) supplies that starting value.

Show reference solution

words = ["python", "ai", "python", "data", "ai"]
counts = {}
for word in words:
    counts[word] = counts.get(word, 0) + 1
print(counts)

5. Write a reusable average function

Write average(values). Return None for an empty list; otherwise return the arithmetic mean. Print average([10, 20, 30]).

Expected printed output

20.0

Check your solution: average([]) should be None. average([5]) should equal 5.0. Try negative values too.

Common mistake: Check the empty case before division to avoid ZeroDivisionError.

Show reference solution

def average(values):
    if not values:
        return None
    return sum(values) / len(values)

print(average([10, 20, 30]))

What should you learn next?

Read the free Python foundations curriculum for explanations and more lessons, or explore the 12-phase Python to AI Engineer track. If a solution fails, inspect the input, the condition and the printed value separately before changing the code.

Exercises authored for PyNex. General language reference: the official Python tutorial.