A Recursive Tale: Python Meets Charlie Cook

Steph
Python
04 Jun, 2024

A Recursive Tale: Python Meets Charlie Cook

I remember vividly twice coming across recursion.

Once during a technical coding test in an interview where one of the questions was about recursion. I remember thinking, “what on earth is recursion?” I frantically scoured the internet trying to understand it… and felt completely lost.

The second time, I was kneedeep in a problem involving deeply nested JSON. It felt like a Russian doll: each layer I peeled back revealed even more nesting. Around that time, I was reading Julia Donaldson books with my kids. One day, I picked up Charlie Cook’s Favourite Book and—bingo—I finally understood recursion.

The Magic of Charlie Cook’s Favourite Book

“Charlie Cook’s Favourite Book” is a delightful story that loops through a chain of tales—each nested inside another:

Charlie starts by reading a book about a pirate.
The pirate finds a book about a girl.
The girl reads a book about a knight… and so on.

Eventually, the story loops all the way back to Charlie Cook, forming a complete circle. Each book contains another, just like a recursive function calling itself.

Understanding Recursion in Python

Recursion is a programming technique where a function calls itself to solve a problem in smaller steps. The process continues until a “base case” is reached a condition that stops the recursion.

It’s like solving a puzzle by breaking it into smaller and smaller pieces… until you hit the smallest unit, solve it, then work your way back up.

Drawing Parallels: Recursion and Nested Stories

1. Nested Structure

Recursion: Like boxes within boxes. Each function call opens a new box calling itself again.
Charlie Cook: Each story opens into another story—books within books, until we return to Charlie.

2. Base Case and Conclusion

Recursion: The base case is a simple, solvable condition that ends the recursive calls.
Charlie Cook: The return to Charlie is the base case—concluding the loop.

3. Elegance and Simplicity

Recursion: Looks complex at first, but offers a clean, elegant way to break down problems.
Charlie Cook: Seamlessly moves through multiple narratives while maintaining a graceful structure.

Recursion in Real-World Applications: Accessing Nested JSON

In real projects, recursion shines when working with nested JSON—a format often used for APIs and data structures.

Here’s a simplified Python example:

def print_stories(data):
    if isinstance(data, dict):
        for key, value in data.items():
            print(f"Key: {key}")
            print_stories(value)
    elif isinstance(data, list):
        for item in data:
            print_stories(item)
    else:
        print(f"Value: {data}")

This function recursively walks through all levels of a nested JSON structure, just like reading every story inside Charlie Cook’s Favourite Book.

Conclusion

Recursion in Python and the storytelling structure of Charlie Cook’s Favourite Book share a magical similarity. Both explore layers within layers, breaking down a journey into smaller chapters.

Just as Charlie’s tale loops back with satisfying closure, recursion unpacks complex problems by peeling them into solvable pieces—each one returning until the problem is fully resolved.

By exploring both programming and children’s stories, we’re reminded that learning doesn’t always come from a tutorial. Sometimes, it’s found in a bedtime story.

A Recursive Tale: Python Meets Charlie Cook