curriculum/challenges/english/blocks/learn-interfaces-by-building-an-equation-solver/664eec7f38234443b42c206f.md
Your equation is currently represented as 11x**2 -1x +1 = 0, but it would be nice not to display the coefficient multiplying \( x \) when it's equal to one. So that equation is represented as 11x**2 -x +1 = 0.
Import the re module. You are going to use a regular expression to substitute the coefficients for this case during the next steps.
You should import the re module.
({ test: () => assert(runPython(`_Node(_code).has_import("import re")`)) })
from abc import ABC, abstractmethod
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--fcc-editable-region--
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")
self.coefficients = {(len(args) - n - 1): arg for n, arg in enumerate(args)}
def __init_subclass__(cls):
if not hasattr(cls, "degree"):
raise AttributeError(
f"Cannot create '{cls.__name__}' class: missing required attribute 'degree'"
)
def __str__(self):
terms = []
for n, coefficient in self.coefficients.items():
if not coefficient:
continue
if n == 0:
terms.append(f'{coefficient:+}')
elif n == 1:
terms.append(f'{coefficient:+}x')
else:
terms.append(f"{coefficient:+}x**{n}")
equation_string = ' '.join(terms) + ' = 0'
return equation_string.strip('+')
@abstractmethod
def solve(self):
pass
@abstractmethod
def analyze(self):
pass
class LinearEquation(Equation):
degree = 1
def solve(self):
a, b = self.coefficients.values()
x = -b / a
return x
def analyze(self):
slope, intercept = self.coefficients.values()
return {'slope': slope, 'intercept': intercept}
class QuadraticEquation(Equation):
degree = 2
def __init__(self, *args):
super().__init__(*args)
a, b, c = self.coefficients.values()
self.delta = b**2 - 4 * a * c
def solve(self):
pass
def analyze(self):
pass
lin_eq = LinearEquation(2, 3)
print(lin_eq)
quadr_eq = QuadraticEquation(11, -1, 1)
print(quadr_eq)