Python 101: The Absolute Minimum You Need to Know

“If you understand this banana, you understand Python.”

Learning Python can feel overwhelming — variables, loops, functions, classes… it’s a lot. Of course, to truly master Python, you need to understand all these concepts in depth. But in 2025, we learn by building things, not walking through the definitions one by one.

So, let’s start with the absolute minimum you need to know to get going with Python, using a simple example: a banana. 🍌

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Banana 🍌

Let’s code up a banana in Python.
This banana will age over time, and change color depending on how many days have passed.

class Banana:
    def __init__(self):
        self.days = 0

    def age(self, days):
        for _ in range(days):
            self.days += 1

        if self.days > 10:
            color = "brown"
        else:
            color = "yellow"

        print(f"This banana is now {color}")

banana = Banana()
banana.age(14)

You just used the fundamentals of Python, all at once! Let’s peel back the layers one-by-one (pun intended), and see what’s going on here. 🥳

1. Variables

self.days = 0
color = "yellow"

Variables are used to store data. Simple as that.

2. Functions

def age(self, days):
    ...

Functions are reusable blocks of code. They take input (days) and do something with it.

3. Loops

for _ in range(days):
    self.days += 1

This for loop runs once for each day passed, adding 1 to the banana’s age.

4. Conditionals (if/else)

if self.days > 10:
    color = "brown"
else:
    color = "yellow"

This is decision-making: we check how old the banana is and assign a color accordingly.

5. Classes and Objects

class Banana:
    ...

You defined a class — a blueprint for bananas.

Then you made a real banana:

banana = Banana()
banana.age(14)

And you ran the method on that object. Boom.

Output

➜ python banana.py
This banana is now brown

Why? Because 14 days have passed, and the banana turned brown. 🍌💀

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You just learnt 5 key concepts in Python from 14 lines of code. In fact, these concepts are the building blocks of almost every Python program you’ll write. You can now create more complex programs by combining these concepts.

Want to play around? Here’s the collab notebook to run this code.

What’s Next?

Next step is to continue learning a few more basics. We will try building a fridge to learn concepts like dictionaries, lists, and more complex logic.

If this helped, share it with a friend learning to code.

Happy coding! 🚀