curriculum/challenges/english/blocks/learn-interfaces-by-building-an-equation-solver/667a8d7a735cf221729570ff.md
Add another case for when the equation is quadratic. Use a dictionary with the same format returned by the analyze method of QuadraticEquation.
Then, assign details_list a list containing two strings with the format concavity = <concavity> and <min_max> = (<x>, <y>), respectively. Format <x> and <y> to display 3 decimal digits.
Finally, after the match/case block, iterate through details_list and add each item to the current value of output_string. Make sure that each string item ends with a newline character. Do not use any additional format option here.
You should not modify the subject value of your match statement.
({ test: () => assert(runPython(`_Node(_code).find_function("solver").find_matches()[1].find_match_subject().is_equivalent("details")`)) })
You should not modify your existing case block.
({ test: () => runPython(`
case = _Node(_code).find_function("solver").find_matches()[1].find_match_cases()[0]
assert case.find_case_pattern().is_equivalent("{'slope': slope, 'intercept': intercept}")
assert case.find_body().is_equivalent("details_list = [f'slope = {slope:.3f}', f'y-intercept = {intercept:.3f}']")
`) })
You should create a new case block for when equation is a quadratic equation.
({ test: () => assert(runPython(`len(_Node(_code).find_function("solver").find_matches()[1].find_match_cases()) == 2`)) })
You should create a for loop to iterate over details_list.
({ test: () => assert(runPython(`_Node(_code).find_function("solver").find_for_loops()[1].find_for_iter().is_equivalent("details_list")`)) })
Your solver function should return a different string.
({ test: () => runPython(`
expected1 = """
----Linear Equation-----
4x +3 = 0
-------Solutions--------
x = -0.750
--------Details---------
slope = 4.000
y-intercept = 3.000
"""
eq1 = LinearEquation(4, 3)
actual1 = solver(eq1)
assert expected1 == actual1
expected2 = """
---Quadratic Equation---
x**2 -3x +1 = 0
-------Solutions--------
x1 = +2.618
x2 = +0.382
--------Details---------
concavity = upwards
min = (1.500, -1.250)
"""
eq2 = QuadraticEquation(1, -3, 1)
actual2 = solver(eq2)
assert expected2 == actual2
`) })
from abc import ABC, abstractmethod
import re
class Equation(ABC):
degree: int
type: str
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'"
)
if not hasattr(cls, "type"):
raise AttributeError(
f"Cannot create '{cls.__name__}' class: missing required attribute 'type'"
)
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 re.sub(r"(?<!\d)1(?=x)", "", equation_string.strip("+"))
@abstractmethod
def solve(self):
pass
@abstractmethod
def analyze(self):
pass
class LinearEquation(Equation):
degree = 1
type = 'Linear Equation'
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
type = 'Quadratic Equation'
def __init__(self, *args):
super().__init__(*args)
a, b, c = self.coefficients.values()
self.delta = b**2 - 4 * a * c
def solve(self):
if self.delta < 0:
return []
a, b, _ = self.coefficients.values()
x1 = (-b + (self.delta) ** 0.5) / (2 * a)
x2 = (-b - (self.delta) ** 0.5) / (2 * a)
if self.delta == 0:
return [x1]
return [x1, x2]
def analyze(self):
a, b, c = self.coefficients.values()
x = -b / (2 * a)
y = a * x**2 + b * x + c
if a > 0:
concavity = 'upwards'
min_max = 'min'
else:
concavity = 'downwards'
min_max = 'max'
return {'x': x, 'y': y, 'min_max': min_max, 'concavity': concavity}
def solver(equation):
if not isinstance(equation, Equation):
raise TypeError("Argument must be an Equation object")
output_string = f'\n{equation.type:-^24}'
output_string += f'\n\n{equation!s:^24}\n\n'
output_string += f'{"Solutions":-^24}\n\n'
results = equation.solve()
match results:
case []:
result_list = ['No real roots']
case [x]:
result_list = [f'x = {x:+.3f}']
case [x1, x2]:
result_list = [f'x1 = {x1:+.3f}', f'x2 = {x2:+.3f}']
for result in result_list:
output_string += f'{result:^24}\n'
output_string += f'\n{"Details":-^24}\n\n'
--fcc-editable-region--
details = equation.analyze()
match details:
case {'slope': slope, 'intercept': intercept}:
details_list = [f'slope = {slope:.3f}', f'y-intercept = {intercept:.3f}']
--fcc-editable-region--
return output_string
lin_eq = LinearEquation(2, 3)
quadr_eq = QuadraticEquation(1, 2, 1)
print(solver(lin_eq))