EX Exercises

1. Basic Data Types – “What is it?”

Task:
You have defined the following variables:

a = 42
b = 3.14
c = "Hello"
d = True
e = [1, 2, 3]

Question:
Which of the following statements is false?
A) a is an int
B) b is a float
C) c is a str
D) d is a bool
E) e is a list
F) a can be used as a float
G) c can be concatenated with a number using +

Explain why the false statement is incorrect.

2. Working with Strings and Operators – “What comes out?”

Task:
What is printed when the following code runs?

text = "Python"
num = 3
result = text * num + " is awesome!"
print(result)

Questions:

  • Why is text * num not interpreted as addition?
  • What happens if you try text + num?
  • How can you convert num to a string so that concatenation works?

3. Conditionals – “Which condition fits?”

Task:
You have a function that checks if a student passed:

def check_pass(mark):
    if mark >= 50:
        return "Passed"
    elif mark >= 40:
        return "Not passed, but retake possible"
    else:
        return "Not passed"

Question:
Which of the following statements is correct?
A) All test cases are correct.
B) Only check_pass(40) is wrong.
C) check_pass(45) should return “Passed”.
D) The function is flawed because 40 is not eligible for a retake.

Explain why your answer is correct.

4. Object Data Types – “Which structure fits?”

Task:
You want to store the following data:

  • Names of 5 students
  • Their grades in Math, German, and English
  • The average grade per student

Question:
Which data structure (list, array, DataFrame) is best suited?
Justify your choice with at least three reasons.
How would you calculate the average grade?
Write your solution in Python.

5. Loops – “What is the output?”

Task:
What is printed when this loop runs?

for i in range(1, 6):
    if i % 2 == 0:
        print(f"{i} is even")
    else:
        print(f"{i} is odd")

Questions:

  • What happens if you replace range(1, 6) with range(0, 6)?
  • How can you modify the range() to print only even numbers?
    Write your solution.

6. Working with Files (CSV) – “Find the error”

Task:
You have the following code to read a CSV file:

import pandas as pd
df = pd.read_csv("books.csv")
print(df.head())

Question:
Could the following three errors cause the code to fail?

  • The file is in the wrong format (e.g., .xlsx)
  • The encoding is incorrect
  • The delimiter is wrong

How can you catch and prevent these errors?
Write a robust version of the code using try/except blocks.

7. Simple Visualisations – “What does it say?”

Task:
You have a DataFrame with the following data:

data = {
    "Month": ["Jan", "Feb", "Mar", "Apr"],
    "Sales": [100, 150, 200, 180]
}
df = pd.DataFrame(data)

You create a bar chart using df.plot(kind='bar').

Questions:

  • What does the chart show?
  • Why is a bar chart better than a pie chart for this data?
  • How could you improve the chart (e.g., with title, axis labels)?

📌 8. Creative Task – “Write your own function” (Creativity & Application)

Task:
Write a function that:

  • Takes a list of numbers
  • Filters only the even numbers
  • Calculates the average of the even numbers
  • Prints a message:
    • If average ≥ 50: “Good performance!”
    • If average < 50: “Still room for improvement.”

Write the function in Python.

Hint:

  • Use for loop or list comprehension
  • Use sum() and len()
  • Use print() to output results

Updated: