Learn Interfaces by Building an Equation Solver - Step 17

Python
1

Tell us what’s happening:

I was syucked at this step, who can support to have a look. Thanks in advance.

    coefficients = {}
    for i in range(len(args)-1,-1,-1):
        coefficients[str(i)] = args[len(args)-1-i]

Your code so far

from abc import ABC, abstractmethod

class Equation(ABC):
    degree: int
    
    def __init__(self, *args):
        if (self.degree + 1) != len(args):
            raise TypeError(
                f"'Equation' object takes {self.degree + 1} positional arguments but {len(args)} were given"
            )
        if any(not isinstance(arg, (int, float)) for arg in args):
            raise TypeError("Coefficients must be of type 'int' or 'float'")
        if args[0] == 0:
            raise ValueError("Highest degree coefficient must be different from zero")

# User Editable Region

        
        coefficients = {}
        for i in range(len(args)-1,-1,-1):
            coefficients[str(i)] = args[len(args)-1-i]
        

# User Editable Region

    def __init_subclass__(cls):
        if not hasattr(cls, "degree"):
            raise AttributeError(
                f"Cannot create '{cls.__name__}' class: missing required attribute 'degree'"
            )
    
    @abstractmethod
    def solve(self):
        pass
        
    @abstractmethod
    def analyze(self):
        pass
        
class LinearEquation(Equation):
    degree = 1
    
    def solve(self):
        pass
    
    def analyze(self):
        pass

    
lin_eq = LinearEquation(2, 3)
a = (2,4)
c = {key:val for key, val in enumerate(a)}
print(c)

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Challenge Information:

Learn Interfaces by Building an Equation Solver - Step 17

2

Hi @wenlong.zhang198809

You should declare an attribute named coefficients within your __init__ method.

You need to start with an attribute, not a variable.

Happy coding

3

Thanks, I forget to add an attribute. Now it’s solved.

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