Help with string formatting in classes

[brthurr]

Hello all. I'm currently taking an Intro to Python course, and I'm on the lesson where we're dealing with Class composition. In the exercise, I have two Py scripts:

creating_classes.py:

class Car:
    """
    Car models a car w/ tires and an engine
    """

    def __init__(self, engine, tires):
        self.engine = engine
        self.tires = tires

    def description(self):
        print(f"A car with an {self.engine} engine, and {self.tires} tires")

tire.py:

class Tire:
    """
    Tire represents a tire that would be used with an automobile.
    """

    def __init__(self, tire_type, width, ratio, diameter,
                 brand='', construction='R'):
        self.tire_type = tire_type
        self.width = width
        self.ratio = ratio
        self.diameter = diameter
        self.brand = brand
        self.construction = construction

    def __repr__(self):
        """
        Represent the tire's information in the standard notation present
        on the side of the tire. Example: 'P215/65R15'
        """
        return (f"{self.tire_type}{self.width}/{self.ratio}"
                + f"{self.construction}{self.diameter}")

The video in the code (where the instructor is using Python 3.7) shows the output as follows:

Output:
$ python3.7 -i creating_classes.py
>>> from tire import Tire
>>> tire = Tire('P', 205, 55, 15)
>>> tires = [tire, tire, tire, tire]
>>> honda = Car(tires=tires, engine='4-cylinder')
>>> honda.description()
A car with a 4-cylinder engine, and [P205/55R15, P205/55R15, P205/55R15, P205/55R15] tires

However, when I run the script (using both Python 3.9 and 3.10), I get the following:

Output:
(learning_python) learning_python $ python3.10 -i creating_classes.py 
>>> from tire import Tire
>>> tire = ('P', 205, 55, 15)
>>> tires = [tire, tire, tire, tire]
>>> honda = Car(tires=tires, engine='4-cylinder')
>>> honda.description()
A car with a 4-cylinder engine and [('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15)] tires

Any idea why the output is formatted this way, as opposed to the way it should be, with proper formatting in the fstring?

Thanks for looking!

[Jeff900]

Is there a particular output you expect? Other than what you get? This is in fact pretty correct what is printed. Because it is printing the whole object (meaning it is printing al the items from the list from the tires). If you want particular items from the tire object, a different approach is needed.

[brthurr]

I expected this:

Output:
A car with a 4-cylinder engine, and [P205/55R15, P205/55R15, P205/55R15, P205/55R15] tires

I got this:

Output:
A car with a 4-cylinder engine and [('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15)] tires

The script ignored the formatting of the fstring in tire.py. When I run it in 3.7, it works as expected. Obviously something changed between 3.7 and 3.9, I'm just wondering if it is a bug or if there's now another way to code in 3.9+ to get the desired formatting.

[BashBedlam]

The difference is, You wrote:

tire = ('P', 205, 55, 15)

Where as the instructor wrote:

tire = Tire('P', 205, 55, 15)

[brthurr]

The difference is, You wrote:

tire = ('P', 205, 55, 15)

Where as the instructor wrote:

tire = Tire('P', 205, 55, 15)

You're my hero. I've been banging my head against the wall.

[Jeff900]

I expected this:

Output:
A car with a 4-cylinder engine, and [P205/55R15, P205/55R15, P205/55R15, P205/55R15] tires

I got this:

Output:
A car with a 4-cylinder engine and [('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15), ('P', 205, 55, 15)] tires

The script ignored the formatting of the fstring in tire.py. When I run it in 3.7, it works as expected. Obviously something changed between 3.7 and 3.9, I'm just wondering if it is a bug or if there's now another way to code in 3.9+ to get the desired formatting.

I tried with 3.9.1 and the result is correct.

Output:
Python 3.9.1 (tags/v3.9.1:1e5d33e, Dec  7 2020, 17:08:21) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from car_tire import Car, Tire
>>> tire = Tire('P', 205, 55, 15)
>>> tires = [tire, tire, tire, tire]
>>> tires
[P205/55R15, P205/55R15, P205/55R15, P205/55R15]
>>> honda = Car(tires=tires, engine='4-cylinder')
>>> honda.description()
A car with an 4-cylinder engine, and [P205/55R15, P205/55R15, P205/55R15, P205/55R15] tires

The only difference is that I putted both classes in de same file and imported them both with the import statement.

[Jeff900]

The difference is, You wrote:

tire = ('P', 205, 55, 15)

Where as the instructor wrote:

tire = Tire('P', 205, 55, 15)

Sharp! I didn't saw it either. But that explains a lot.