Homework_1.py

# -*- coding: utf-8 -*-
"""
Read the comments in this file.  The comments contain problem statements.
Do your best to write code that satisfies what is being requested in the
problem statements.

This homework will be handed in at the start of the next class by depositing
the file in the class folder in the Y drive.  Place the homework in your
personal folder.  Name the file {first name}_{last name}_homework1.py.
For example: philip_blankenau_homework1.py
"""



###############################################################################
# Write a function that coverts a Fahrenheit temperature to Celcius.
###############################################################################
fahrenheit = 32 #insert number that you want to convert

def conversion(fahrenheit):
    '''Converts temperature in Fahrenheit to Celsius'''
    return (fahrenheit - 32) / 1.8

print(conversion(fahrenheit))

###############################################################################
# Amortizied loan payments
#
# You purchased a used car for 13,000.00 with no down payment, so you take
# out a $13,000.00 loan.
# You want to know what the payments will be if you pay back your loan in 5
# years, and you write the code below.  The formula for the monthly payment
# is here: https://en.wikipedia.org/wiki/Amortization_calculator
#
# Convert the code below to a function or a functions you can reuse for other
# loans.
###############################################################################

principle = 13000.0
annual_percentage_rate = 4.0 # %
years = 5.0
payments_per_year = 12.0

def monthly_interest(annual_percentage_rate, payments_per_year):
    '''Calculates monthly interest'''
    val = annual_percentage_rate / payments_per_year / 100.0
    return val 

monthly_interest = monthly_interest(annual_percentage_rate, payments_per_year)

def total_num_payments(years, payments_per_year):
    '''Calculates total number of payments needed to pay the loan'''
    val = years * payments_per_year
    return val

total_num_payments = total_num_payments(years, payments_per_year)

def monthly_payment(principle, monthly_interest, total_num_payments):
    '''Calculates the monthly payment'''
    val = (1 + monthly_interest) ** total_num_payments
    return (principle * monthly_interest * val / (val - 1))

print(round(monthly_payment(principle, monthly_interest, total_num_payments), 2))
    
###############################################################################
# Uncomment the line where print(x) appears.  Run the file and examine
# the output.
# Write to explain why there is a NameError "name 'x' is not defined" even
# though we defined x in the function.
#
# ANSWER: This gives you an error because variable x is defined only on a local scope,
# inside of a function. If print(x) was inside of that function it would return 
# a value of 5, but since we are asking to print a value on a global scale where
# value x is not defined we get an error
#
# NOTE: Using x as a name in previous exercises can cause an issue here.
###############################################################################

def multiply_by_five(number):
    """Multiplies number by 5."""
    x = 5
    return number * x

multiply_by_five(5)
#print(x)

monthly_interest = annual_percentage_rate / payments_per_year / 100.0
total_num_payments = years * payments_per_year
monthly_payment = (principle* monthly_interest* ((1 + monthly_interest) ** total_num_payments)
/ (((1 + monthly_interest) ** total_num_payments) - 1))
print(round(monthly_payment, 2))