curriculum/challenges/english/blocks/learn-interfaces-by-building-an-equation-solver/663a32735b317af9812eb0d7.md
In linear equations in the form \( ax + b = 0 \), the slope is simply the coefficient \( a \), and the y-intercept is the coefficient \( b \).
You are going to use the analyze method to provide additional information about the equation. Inside the analyze method, unpack the coefficients into the variables slope and intercept.
Then, return a dictionary with the keys 'slope' and 'intercept' and the values of the slope and the y-intercept, respectively. After that, call analyze on lin_eq and print the result.
You should unpack the values stored in the coefficients attribute into the variables slope and intercept inside the analyze method.
({ test: () => assert(runPython(`_Node(_code).find_class("LinearEquation").find_function("analyze").has_stmt("slope, intercept = self.coefficients.values()")`)) })
The analyze method should return a dictionary with the keys 'slope' and 'intercept' and the values of the slope and the y-intercept, respectively.
({ test: () => runPython(`
eq = LinearEquation(2.2, 1.5)
a = eq.analyze()
assert a['slope'] == 2.2, "Expected different slope"
assert a['intercept'] == 1.5, "Expected different intercept"
`) })
You should call the analyze method of your lin_eq object.
({ test: () => assert(runPython(`_Node(_code).has_call("print(lin_eq.analyze())")`)) })
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")
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')
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
--fcc-editable-region--
def analyze(self):
pass
lin_eq = LinearEquation(2, 3)
print(lin_eq)
print(lin_eq.solve())
--fcc-editable-region--