Magic Methods

So by a super cool and awesome and really amazing developer who I work with sometimes, I have been set the task of trying to figure out how we would go about sorting two instances of the same class - based on the value of one of their attributes.

magic methods - taylor swift folklore aesthetic and vibe

So what are magic methods?

Magic methods are "special methods describing how certain objects should behave."

They are "dunder methods" (sounds like something out of a fantasy novel?) like __init__, __repr__ and __lt__. I came across these when I was first learning Python/Django for my job interview.

These methods apparently indicate that these methods "shouldn't be called directly by the programmer, they are normally called by the interpreter itself." Source: https://blog.cambridgespark.com/magic-methods-a8d93dc55012

There is a thing called __new__ that comes before the __init__ method, but we are not going into this today.

I am not going to be going too much into __str__ and __repr__ today which are the two main methods for representing your classes because I have this task that I have been given and I want to focus on it so much.

Comparison methods

I wonder if comparison methods are my solution? Actually I know that I need the __lt__ method - I just don't know how to use it yet - is this a comparison method?

For context this is the class that I built today - so embarrassing - but it'll illustrate it at least. The Susanna can change on any given day - she can be programming in a different language, have a new favourite colour, and have a different amount of apples with her at work (I love fruits).

class Susanna:

def __init__(self, language: str, color: str, apples: int) -> None:

self.language = language

self.color = color

self.apples = apples

def __repr__ (self) -> str:

return f"Susanna id={id(self)}"

def __str__ (self) -> str:

return f"Today the Susanna is programming in {self.language},

likes the color {self.color}, and has {self.apples} apples with her

today. p.s. BANANA"

The task I have is to make sure that if I create two instances of the Susanna class, I can compare them by the number of apples.

So how do I do this - how?!

I was right! __lt__ is a comparison method. It defines the behaviour of the less-than > operator. But how do I use this then please - how???!

I got this far and then I realised I hadn't actually understood the assignment properly.

Was I meant to actually use the __lt__ method? Isn't it a magic method? What is it that it is actually trying to achieve?

THIS HAS WORKED

My code is an absolute shambles - I had to to it all again because my IDE deletes things when I click out - I need to use a better one.

But here we go - it worked. Based on the IDs, it looks like it returned the list in the opposite order than we wrote it in and that is what we wanted it to be - we wanted it to be in ascending order - I think. !!!

I'm not sure if this works for sure but I will check with my mentor tomorrow - thank you so so so much for reading.