Hello, Python

Real AI engineers write code. Don't worry — we'll start gently, and you'll have a working program by the end of this chapter. Code is just clear instructions for a computer, written one line at a time.

We'll use Python, the language most AI is built with. It reads almost like English.

Step 0 — Open a Python notebook

You'll write code in a free browser tool, so there's nothing to install.

With a grown-up, open Google Colab (colab.research.google.com) and start a New notebook. (A "notebook" lets you run little chunks of code one at a time — perfect for learning.)
You'll type code into a cell and press the ▶ play button (or Shift+Enter) to run it.

Stay safe

Colab needs a Google account, so set it up with a parent or guardian (or use their account with them nearby). Notebooks you make are private to you. As always, don't put real personal details in your code.

Step 1 — Make the computer talk

Type this and run it:

print("Hello! I am your first program.")

print(...) shows whatever is inside the quotes. You just gave the computer an instruction and it obeyed. 🎉

Step 2 — Variables: boxes that remember

A variable is a labeled box that stores a value:

name = "Robo"
age = 1
print(name + " is " + str(age) + " year old.")

name holds text (called a string).
age holds a number.
str(age) turns the number into text so it can join the sentence.

Step 3 — Ask the user a question

input(...) lets your program ask and remember the answer:

user_name = input("What's your name? ")
print("Nice to meet you, " + user_name + "!")

Run it, type your name, and watch your program reply. Now it's interactive.

Step 4 — Make decisions with if / else

Programs get smart when they choose:

mood = input("How are you? (good/bad) ")

if mood == "good":
    print("Awesome! Let's build something. 🚀")
else:
    print("That's okay. Coding always cheers me up!")

Notice the indentation (the spaces). Python uses it to know which lines belong to the if. Keep it tidy — it matters!

Step 5 — Repeat with a loop

A loop repeats lines without copy-pasting:

for i in range(3):
    print("Counting... " + str(i + 1))

This runs three times. Loops will let your chatbot keep talking instead of stopping after one reply.

Check yourself

What does print() do?
What's a variable?
What does input() give you, and why is if / else useful?

Project — Build a rule-based chatbot 🛠️

This chatbot uses rules you write (no AI yet — that's Chapter 7!). It shows you exactly how a program "thinks."

print("🤖 QuizBot: Hi! Answer my questions. Type 'quit' to stop.")
score = 0

questions = [
    ("What planet do we live on? ", "earth"),
    ("What color is the sky on a clear day? ", "blue"),
    ("2 + 2 = ? ", "4"),
]

for question, answer in questions:
    reply = input(question).lower().strip()
    if reply == "quit":
        break
    if reply == answer:
        print("✅ Correct!")
        score = score + 1
    else:
        print("❌ Not quite. The answer was: " + answer)

print("🤖 You scored " + str(score) + " out of " + str(len(questions)) + "!")

Type it in (typing it yourself helps you learn more than pasting).
Run it and play your quiz.
Make it yours: add your own questions to the list, change QuizBot's name, or add a victory message when the score is perfect.

Your turn

Add a personality. Give your bot a name variable and have it use the player's name in every reply. Then add a final if score == len(questions): message like "🏆 Perfect score, genius!"

Make it simpler · ages 9–11

Just do Steps 1–4 with a grown-up. The big win is making the computer ask your name and reply with an if / else. That tiny program is real coding — be proud!

Level up · ages 13–16

Refactor your quiz into a function so you can reuse it:

def ask(question, answer):
    return input(question).lower().strip() == answer

Then call ask(...) for each question and count the True results. Functions are how engineers avoid repeating themselves — you'll lean on them hard in the next chapters.

What you learned

print, variables, and input let your program talk and listen.
if / else makes decisions; loops repeat work.
You built a real rule-based chatbot in Python.

You've earned the Code Cadet badge. 🏅

Your bot follows rules you wrote. Next, you'll plug a real AI brain into your code, so it can answer anything. That's Chapter 7: Your First AI App in Code.

In this chapter you'll