__str__() question /u/ye_esquilax Python Education

I’ve been teaching myself Python using the Python Crash Course book, and now that I’ve reached the end of it I’ve been going through various tutorial websites to practice/supplement what I’ve learned. However, I’ve run into something strange.

As far as I can see, the Python Crash Course book does not mention __str__(). When I started looking at some class tutorials, as that’s something I’m struggling with, I’ve run into examples where they use a method called __str__().

I’m shaky as to what it does, and I’m even more confused by the examples. I see one on https://www.w3schools.com/python/python_classes.asp which uses the following code:

class Person: def __init__(self, name, age): self.name = name self.age = age def __str__(self): return f"{self.name}({self.age})" p1 = Person("John", 36) print(p1) 

When run, it returns John 36. Then there’s another example where the __str__() method is not used, and it returns <__main__.Person object at 0x15039e602100>.

Okay, fine. So I need to use __str__() for this to work. But in the Python Crash Course, it shows an example with a similar class, and it does not use a __str__() method, and it works fine:

class Car: def __init__(self, make, model, year): self.make = make self.model = model self. year = year def get_descriptive_name(self): long_name = f"{self.year} {self.make} {self.model}" return long_name.title() my_new_car = Car("Audi", "a4", "2024") print(my_new_car.get_descriptive_name()) 

This returns “2004 Audi A4”. But it does not use a __str__() method. Why?

I’ve been teaching myself Python using the Python Crash Course book, and now that I’ve reached the end of it I’ve been going through various tutorial websites to practice/supplement what I’ve learned. However, I’ve run into something strange.

As far as I can see, the Python Crash Course book does not mention __str__(). When I started looking at some class tutorials, as that’s something I’m struggling with, I’ve run into examples where they use a method called __str__().

I’m shaky as to what it does, and I’m even more confused by the examples. I see one on https://www.w3schools.com/python/python_classes.asp which uses the following code:

class Person: def __init__(self, name, age): self.name = name self.age = age def __str__(self): return f"{self.name}({self.age})" p1 = Person("John", 36) print(p1) 

When run, it returns John 36. Then there’s another example where the __str__() method is not used, and it returns <__main__.Person object at 0x15039e602100>.

Okay, fine. So I need to use __str__() for this to work. But in the Python Crash Course, it shows an example with a similar class, and it does not use a __str__() method, and it works fine:

class Car: def __init__(self, make, model, year): self.make = make self.model = model self. year = year def get_descriptive_name(self): long_name = f"{self.year} {self.make} {self.model}" return long_name.title() my_new_car = Car("Audi", "a4", "2024") print(my_new_car.get_descriptive_name()) 

This returns “2004 Audi A4”. But it does not use a __str__() method. Why?