How to Start Coding – Part 6: Number Guessing Game

Prologue:

Welcome back! Last time, you learned variables, if/else, and loops in Python. Today we’re using them to build your very first Python game: a number guessing game.

Here’s how it works. The computer picks a secret number between 1 and 20. You try to guess it, and the computer tells you if your guess is too high or too low. Keep guessing until you get it!

Let’s begin!

Chapter 1: The code!

Open IDLE, click File > New File, and save it as guessing_game.py. Then type this in:

import random

secret = random.randint(1, 20)
guess = 0

print("I'm thinking of a number between 1 and 20...")

while guess != secret:
    guess = int(input("Take a guess: "))

    if guess < secret:
        print("Too low!")
    elif guess > secret:
        print("Too high!")
    else:
        print("You got it! The number was " + str(secret) + "!")

Press F5 to play. Since the number is random, your game will be different every time. Here’s an example:

I'm thinking of a number between 1 and 20...
Take a guess: 10
Too high!
Take a guess: 5
Too low!
Take a guess: 8
You got it! The number was 8!

Chapter 2: How it works!

There are three new things in this game.

1. Random numbers

import random gives your program a toolbox of random tools. Then random.randint(1, 20) picks a random whole number from 1 to 20. This is just like the pick random (1) to (20) block in Scratch!

2. The while loop

while guess != secret: means “keep repeating while the guess is not equal to the secret number.” The != sign means “not equal.” Once you guess right, the loop stops. In Scratch, this is the repeat until <> block.

3. elif

elif is short for “else if.” It lets you check more than two options. Our game has three: too low, too high, or just right.

 

One more small thing: str(secret) turns the number back into text so we can glue it into our message with +. It’s the opposite of int() from last time.

 

IMPORTANT NOTE

If you type a word like banana instead of a number, the game will crash with a ValueError. That’s because int() doesn’t know how to turn “banana” into a number. Just run the game again and stick to numbers!

Chapter 3: Future Steps

Congrats, you just made your first Python game! In Part 7, we’ll build a Magic 8-Ball that answers your yes-or-no questions, and you’ll learn about lists.

CHALLENGE

Make the game count how many guesses it took you. Hint: make a variable called tries that starts at 0, and add 1 to it every time the loop runs.

If you get stuck or have any questions, feel free to contact me! And leave a comment with how many tries it took you to win!