curriculum/challenges/english/blocks/learn-special-methods-by-building-a-vector-space/65fa9402d1fb5516aa42159d.md
Feel free to modify v3 so that it sums an R2Vector instance with an object of a different type, such as an integer or a string. You will be able to see a TypeError message printed on the console.
Then, restore the original line and create a new variable v4. Assign the difference between v1 and v2 to your new variable and print the result following the same structure as the previous f-string.
You should declare a variable v4 and assign it the difference between v1 and v2.
({
test: () => assert(runPython(`
_Node(_code).has_stmt("v4 = v1 - v2")
`))
})
You should print f'v1 - v2 = {v4}'.
({ test: () => assert(runPython(`_Node(_code).has_call("print(f'v1 - v2 = {v4}')")`)) })
class R2Vector:
def __init__(self, *, x, y):
self.x = x
self.y = y
def norm(self):
return sum(val**2 for val in vars(self).values())**0.5
def __str__(self):
return str(tuple(getattr(self, i) for i in vars(self)))
def __repr__(self):
arg_list = [f'{key}={val}' for key, val in vars(self).items()]
args = ', '.join(arg_list)
return f'{self.__class__.__name__}({args})'
def __add__(self, other):
if type(self) != type(other):
return NotImplemented
kwargs = {i: getattr(self, i) + getattr(other, i) for i in vars(self)}
return self.__class__(**kwargs)
def __sub__(self, other):
if type(self) != type(other):
return NotImplemented
kwargs = {i: getattr(self, i) - getattr(other, i) for i in vars(self)}
return self.__class__(**kwargs)
class R3Vector(R2Vector):
def __init__(self, *, x, y, z):
super().__init__(x=x, y=y)
self.z = z
--fcc-editable-region--
v1 = R2Vector(x=2, y=3)
v2 = R2Vector(x=0.5, y=1.25)
print(f'v1 = {v1}')
print(f'v2 = {v2}')
v3 = v1 + v2
print(f'v1 + v2 = {v3}')
--fcc-editable-region--