CODEWITHSUNDEEP
python-3.xclass
KOS MOS
KOS MOS

Reputation: 21

Created Class Won't Pass Assertion Check

I have to create a class, and 3 methods within it. We were given a bunch of assertion checks, and I can't seem to get past the first one. This method doesn't pass, so I'm sure that the other two won't either (the other two use the value that I get from the first one). Have I missed something?

class Loan(object):
"""Calculates information regarding Loans."""
def __init__(self,principal,rate,time):
    self.principal = principal
    self.rate = rate
    self.time = time

def calculate_monthly_payment(self):
  """Calculates monthly loan payments"""
  part_1 = self.rate*((1+self.rate)**self.time)
  part_2 = ((1+self.rate)**self.time)-1
  monthly_pmt = self.principal*(part_1//part_2)
  return monthly_pmt

Formula I have to use: enter image description here

Assertion check I was given:

# Testing Loan
loan1 = Loan(100, 0.1, 10)
assert math.isclose(loan1.principal, 100, abs_tol=0.00001), "{} != {}".format(loan1.principal, 100)
assert math.isclose(loan1.rate, 0.1, abs_tol=0.00001), "{} != {}".format(loan1.rate, 0.1)
assert math.isclose(loan1.time, 10, abs_tol=0.00001), "{} != {}".format(loan1.time, 10)
assert math.isclose(loan1.calculate_monthly_payment(), 16.274539488251154, abs_tol=0.00001), "{} != {}".format(loan1.calculate_monthly_payment(), 16.274539488251154)

Assertion Error:

File "main.py", line 161, in main
assert math.isclose(loan1.calculate_monthly_payment(), 16.274539488251154, abs_tol=0.00001), "{} != {}".format(loan1.calculate_monthly_payment(), 16.274539488251154)

AssertionError: 0.0 != 16.274539488251154

Upvotes: 0

Views: 44

Answers (1)

Draconis
Draconis

Reputation: 3491

You're using integer division (//) where you want float division (/) in your second-to-last line. part1 // part2 is rounded to zero, and so you return zero, which is incorrect.

Upvotes: 1

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