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Workshop 2 — Homework

Welcome to your second homework! It has two parts:

  1. Part 1 — Research: Workshop 2 concepts
  2. Part 2 — Python exercises

Deadline: before Workshop 3.

How to submit: push everything to the same GitHub repository you created for Homework 1, then re-send the repository link to your instructor.

Put this homework in its own folder so it does not mix with Homework 1:

cd python-homework        # the repo from Homework 1
mkdir workshop_2_homework
cd workshop_2_homework
# ...create your answers.md and exercise files in here...

When you are done, commit and push from the repository folder:

git add .
git commit -m "Add workshop 2 homework"
git push

If a command fails, read the error message carefully — it usually tells you what is wrong. If you are still stuck, take a screenshot and bring it to the next workshop.

Part 1 — Research: Workshop 2 concepts

Create a file called answers.md and answer the following questions in your own words (1–3 sentences each is enough). It is fine to be wrong — we will review the answers together in the next workshop.

Getting input from the user

  1. What does the input() function do? What data type does it always return — even if the user types 42?
  2. Why do we often wrap input() in int(...) or float(...)? What goes wrong if we forget to?
  3. What does the type() function tell you, and why is it handy when something is not behaving the way you expect?

Working with strings

  1. What do the string methods .upper(), .lower(), and .strip() each do? Give a short example for one of them.
  2. What do the escape sequences \n and \t mean inside a string?

Booleans and truthiness

  1. A comparison like age >= 18 produces a value. What data type is that value?
  2. Why is bool("") False, but bool("0") and bool(" ") are both True? (Hint: think about empty versus not empty.)

Floats and constants

  1. Why does 0.1 + 0.2 == 0.3 print False? What is round() useful for here?
  2. Some programmers write names like MAX_SCORE in ALL_CAPS. What does that naming convention signal to other programmers, and why shouldn't you change such a value later?

Part 2 — Python exercises

Create the files below and write Python code to solve each task. Use only what we have covered so far: variables, data types, type casting, operators, input(), string methods, f-strings, bool(), round(), and constants.

We have not learned if, loops, functions, or lists yet — you do not need any of them for this homework. When you need a True/False answer, just print the boolean, the way we did with "is even" in Homework 1.

Run each file with:

python exercise_1.py

exercise_1.py — Greeting

Ask the user for their name with input(). They might accidentally type extra spaces, so clean the text with .strip(). Then print a greeting on two lines using an f-string, the escape sequence \n, and .upper().

Example run:

What is your name?
   nino
Welcome!
HELLO, NINO!

exercise_2.py — Years to 100

Ask the user for their age. Remember that input() gives you a string, so cast it to an int. Print how many years are left until they turn 100, using an f-string.

Example run:

How old are you?
21
You will turn 100 in 79 years.

exercise_3.py — Celsius → Fahrenheit

Ask for a temperature in Celsius and cast it to a float. Convert it to Fahrenheit with the formula celsius * 9 / 5 + 32. Print the result rounded to 1 decimal place with round().

Example run:

Temperature in Celsius:
36.6
36.6°C is 97.9°F

exercise_4.py — Truthy or falsy

First guess in a comment whether each value below is truthy (True) or falsy (False). Then check your guesses using the self-documenting f-string we saw in class. Finally, print the type() of any one of the values.

# Guess first! Write True or False next to each line:
# bool("")    -> ?
# bool("0")   -> ?
# bool(" ")   -> ?
# bool(0)     -> ?
# bool(-5)    -> ?

print(f"{bool("") = }")
print(f"{bool("0") = }")
print(f"{bool(" ") = }")
print(f"{bool(0) = }")
print(f"{bool(-5) = }")

print(type("0"))

How many did you guess correctly?

exercise_5.py — Circle area

Define a constant PI = 3.14159 (note the ALL_CAPS name — that means "do not change me"). Ask the user for a circle's radius and cast it to a float. Calculate the area with PI * radius ** 2 and print it rounded to 2 decimal places.

Example run:

Radius:
5
A circle with radius 5.0 has area 78.54

exercise_6.py — Fix the bug (bonus)

The program below is supposed to tell the user how old they will be next year, but it crashes. Explain in a comment why it crashes, then fix it so it works.

age = input("How old are you?\n")
print("Next year you will be", age + 1, "years old.")

Hint: what data type does input() give back? Can you add the number 1 to that?

Checklist before you submit

  • answers.md with the Workshop 2 questions answered
  • exercise_1.py … exercise_6.py written and runnable
  • Everything pushed to your GitHub repository (inside a workshop_2_homework/ folder)
  • Repository link sent to the instructor

Helpful links