Lab 02 — Number Guessing Game

Hands-on Lab 35 min Beginner

Objectives

1. Use while True + break for a game loop
2. Apply if/elif/else for game logic
3. Use random.randint() from the standard library
4. Track attempts with a counter
5. Use list comprehensions to analyze a history of guesses

Prerequisites

• Module 02 lessons completed

---

Step 1 — Setup

mkdir ~/python-course/lab-02
cd ~/python-course/lab-02

Create guessing_game.py:

#!/usr/bin/env python3
"""
Lab 02 — Number Guessing Game
Demonstrates control flow, loops, and comprehensions.
"""

import random


def get_difficulty():
    """Let the user choose a difficulty level."""
    print("\nChoose difficulty:")
    print("  1. Easy   (1–50,  10 attempts)")
    print("  2. Medium (1–100,  7 attempts)")
    print("  3. Hard   (1–200,  5 attempts)")

    while True:
        choice = input("Your choice (1/2/3): ").strip()
        match choice:
            case "1": return 50, 10, "Easy"
            case "2": return 100, 7, "Medium"
            case "3": return 200, 5, "Hard"
            case _:   print("Invalid choice — enter 1, 2 or 3.")


def play_game(max_number, max_attempts, difficulty):
    """Run one round of the guessing game."""
    secret = random.randint(1, max_number)
    guesses = []

    print(f"\n{'=' * 45}")
    print(f"  Difficulty: {difficulty}")
    print(f"  Guess a number between 1 and {max_number}")
    print(f"  You have {max_attempts} attempts")
    print(f"{'=' * 45}\n")

    for attempt in range(1, max_attempts + 1):
        # Get valid input
        while True:
            try:
                guess = int(input(f"Attempt {attempt}/{max_attempts}: "))
                if 1 <= guess <= max_number:
                    break
                print(f"  Please enter a number between 1 and {max_number}.")
            except ValueError:
                print("  Invalid input — enter an integer.")

        guesses.append(guess)
        distance = abs(guess - secret)

        if guess == secret:
            print(f"\n  🎉 Correct! The number was {secret}!")
            return True, guesses, attempt

        # Hint based on distance
        if distance <= 5:
            hint = "🔥 Very hot!"
        elif distance <= 15:
            hint = "♨️  Hot!"
        elif distance <= 30:
            hint = "🌤  Warm"
        else:
            hint = "❄️  Cold"

        direction = "higher" if guess < secret else "lower"
        print(f"  {hint} Go {direction}. {max_attempts - attempt} attempts left.")

    print(f"\n  💀 Game Over! The number was {secret}.")
    return False, guesses, max_attempts


def analyze_guesses(guesses, secret):
    """Use comprehensions to analyze guess history."""
    too_low = [g for g in guesses if g < secret]
    too_high = [g for g in guesses if g > secret]
    distances = [abs(g - secret) for g in guesses]

    print(f"\n  📊 Analysis:")
    print(f"     Guesses : {guesses}")
    print(f"     Too low : {too_low}")
    print(f"     Too high: {too_high}")
    if distances:
        print(f"     Best guess distance: {min(distances)}")
        print(f"     Average distance   : {sum(distances) / len(distances):.1f}")


def show_score(wins, losses):
    """Display win/loss statistics."""
    total = wins + losses
    rate = (wins / total * 100) if total > 0 else 0
    print(f"\n  🏆 Score: {wins}W / {losses}L  ({rate:.0f}% win rate)")


def main():
    """Main game loop."""
    print("=" * 45)
    print(f"{'🎮  NUMBER GUESSING GAME':^45}")
    print("=" * 45)

    wins, losses = 0, 0
    secret_tracker = []

    while True:
        max_num, max_att, difficulty = get_difficulty()
        won, guesses, attempts = play_game(max_num, max_att, difficulty)

        secret = None
        for g in guesses:
            if g == guesses[-1] and won:
                secret = g
        if not won:
            secret = None

        if won:
            wins += 1
            print(f"  ✅ Won in {attempts} attempt(s)!")
        else:
            losses += 1

        analyze_guesses(guesses, guesses[-1] if won else -1)
        show_score(wins, losses)

        again = input("\n  Play again? (y/n): ").strip().lower()
        if again != "y":
            break

    print("\n  Thanks for playing! 👋")


if __name__ == "__main__":
    main()

---

Step 2 — Run the Game

python3 guessing_game.py

Verification ✅

=============================================
           🎮  NUMBER GUESSING GAME
=============================================

Choose difficulty:
  1. Easy   (1–50,  10 attempts)
  2. Medium (1–100,  7 attempts)
  3. Hard   (1–200,  5 attempts)
Your choice (1/2/3): 1

=============================================
  Difficulty: Easy
  Guess a number between 1 and 50
  You have 10 attempts
=============================================

Attempt 1/10: 25
  🌤  Warm Go higher. 9 attempts left.
Attempt 2/10: 37
  ♨️  Hot! Go lower. 8 attempts left.
Attempt 3/10: 31

  🎉 Correct! The number was 31!
  ✅ Won in 3 attempt(s)!

  📊 Analysis:
     Guesses : [25, 37, 31]
     Too low : [25]
     Too high: [37]
     Best guess distance: 0
     Average distance   : 5.3

---

Bonus Challenge

Add a leaderboard that persists across games:

1. Store (difficulty, attempts, timestamp) for each win
2. At the end, show the top 3 fastest wins using a list comprehension with sorted
3. Use datetime.now() from the standard library

from datetime import datetime

leaderboard = []
# After a win:
leaderboard.append((difficulty, attempts, datetime.now().strftime("%H:%M:%S")))

# Show top 3
top3 = sorted(leaderboard, key=lambda x: x[1])[:3]
for rank, (diff, att, time) in enumerate(top3, 1):
    print(f"  #{rank}: {diff} in {att} attempts at {time}")

---

Cleanup

No cleanup required — local script only.

---

Summary

In this lab you applied:

• while True + break for the main game loop
• match/case for difficulty selection
• for loop with range() for the attempt counter
• try/except ValueError for input validation
• List comprehensions to analyze the guess history (too_low, too_high, distances)
• min(), sum(), len() with lists built by comprehensions