Comparing Loans in Python - python

I am doing an assignment for my Python class. I almost figured it out but my output is just a little bit different with the one showed in the original problem. When interest rate is 5.125%, I have a Monthly Payment for 189.29, but the output from the problem is 188.28. The original number without format is 189.286. I guess maybe in the finance system, they just simply cut the decimals instead of using "round". I am not sure if there is any way to do that in Python. Here is the problem.
Write a program that lets the user enter the loan amount and loan period in number of years and displays the monthly and total payments for each interest rate starting from 5% to 8%, with an increment of 1/8.
Input:
Loan Amount: 10000
Number of Years: 5
Output:
Interest Rate Monthly Payment Total Payment
5.000% 188.71 11322.74
5.125% 189.29 11357.13
...
7.875% 202.17 12129.97
8.000% 202.76 12165.84
Code:
LoanAmount = float(input("Loan Amount:"))
NumOfYears = float(input("Number of Years:"))
AnnualRate = float(5.0)
print("\nInterest Rate\t" + "Monthly Payment\t" + "Total Payment")
while (AnnualRate <= 8.0):
MonthlyRate = float(AnnualRate/1200)
MonthlyPayment = float(LoanAmount * MonthlyRate / (1- 1/ pow(1+MonthlyRate, NumOfYears *12)))
TotalPayment = format(MonthlyPayment * NumOfYears * 12, ".2f")
print (format(AnnualRate, ".3f"), end = "%\t\t")
print (format(MonthlyPayment, ".2f"), end = "\t\t")
print(TotalPayment, end = "\n")
AnnualRate += 1.0/8

When you work with money use the decimal module. This allows many different rounding modes. For example, round down:
import decimal
payment = decimal.Decimal('189.286')
with decimal.localcontext() as ctx:
ctx.rounding = decimal.ROUND_DOWN
print(round(payment, 2))
Prints:
189.28
Bankers' rounding would be:
decimal.ROUND_HALF_EVEN
Round to nearest with ties going to nearest even integer.
with decimal.localcontext() as ctx:
ctx.rounding = decimal.ROUND_HALF_EVEN
print(round(payment, 2))

Related

amortization/loan table without using pandas

What would be the best way to create a monthly amortization table without using pandas? Say I am given the amount of the loan, the annual interest rate, and the duration in years. How can I make a table that gives the period, beginning balance, principle, interest, and then the ending balance? And then the amount in the ending be equal to 0.
For example if I had a 150,000 loan, 10% rate, and a duration of 25 years (300 months), I don't want to use user input on this though
Formatted something like this (output will be super long I know):
month begin bal. interest principal end bal.
1 xxxx xxxx xxxx xxxx
.
.
I can attach what I have started on, but I know it is horrible lol, I am horrible with formulas/tables in Python it just does not click with me so I am struggling. Anything will help, thanks!
#p = r(pv)/(1-(1+r)**-n)
loan = 150000
rate = 10/100 #10%
term = 25 #25 years
for i in range(loanTerm):
print("month. begin bal. interest. principal. ending bal")
beginB = loanAmt
pv = loan
r = rate/100
n = term*12
p = r(pv)/(1-(1+r)**-n)
^ I know that is a very sad attempt with many errors I am embarrassed LOL just don't even know where to start. Let me know if there is anything I need to clarify!
Well, to start out with, you compute all of your constants before the loop.
#p = r(pv)/(1-(1+r)**-n)
loan = 150000
rate = 10/100 #10%
term = 25
mo_rate = rate/12
mo_term = term*12
factor = (1 + mo_rate) ** mo_term
pmt = round(loan * (mo_rate * factor) / (factor - 1), 2)
print( "Payments are", pmt, "per month")
balance = loan
print( "month\tbal\tint\tprin\tending" )
for i in range(mo_term):
interest = balance * mo_rate
ending = balance + interest - pmt
print( f"{i}\t{balance:.2f}\t{interest:.2f}\t{pmt-interest:.2f}\t{ending:.2f}" )
balance = ending

Working with multiple input variables in Python 3

So I'm very new to coding and I'm learning python so I decided I'd try to make a loan calculator. I made it so when the user inputs their principle, interest rate, and years required to pay the loan in full, it will output their annual payment, their monthly payment, and their total payment for the loan. I made this and it worked. I decided to take it a step further and make it so that after this, if the user inputs their annual income, it will compare their monthly income to their monthly payment and tell them if they need to refinance or not.
Here's the program I made:
principle = float(input("Principle: ")) #principle = the amount of dollars borrowed
rate = float(input("Rate: ")) #rate = the interest rate that is charged each year on unpaid principle
years = float(input("Years: ")) #years = the number of years required to repay the loan in full
payment = ((1 + rate)**years * principle * rate)/((1 + rate)**years - 1)
#lines 7-10 print the annual, monthly, and total payments made respectively
print("Annual payment: ${:,.2f}".format(payment))
print("Monthly payment: ${:,.2f}".format(payment/12))
print("Total paid for the life of the loan: ${:,.2f}".format(payment*years))
principle = float(input("Principle: ")) #principle = the amount of dollars borrowed
rate = float(input("Rate: ")) #rate = the interest rate that is charged each year on unpaid principle
years = float(input("Years: ")) #years = the number of years required to repay the loan in full
payment = ((1 + rate)**years * principle * rate)/((1 + rate)**years - 1)
annualinc = float(input("Annual income: ")) #annualinc = the annual income
#to check if the user needs to refinance or not by comparing their monthly
income to their monthly payment
if (annualinc / 12) <= (payment / 12) and rate > .05:
print("You should refinance")
elif (annualinc / 12) <= (payment / 12):
print("You should seek financial counseling")
else:
print("If you make all your payments, your loan will be paid on time.")
The only way I could get the if statement to work is by having the user re-input every variable between the print statements and the if statement. Whenever I put the variable annualinc = float(input("Annual income: ") at the beginning of the program before the print statements or between the print statements and if statement it would break the line after it with a syntax error. Why did I have to ask for all the variables again and why could I not just ask for the variable annualinc by itself? And why does it not work when I put it with the first group of variables?
edit: I fixed it so I don't have to put in all the variables again! I was missing a parenthesis at the end of the line and I've been copy and pasting the line when I moved it around so the error traveled with it. Sorry for such a rookie mistake and thank you!
Would this suit you?
principle = float(input("Principle: ")) #principle = the amount of dollars borrowed
rate = float(input("Rate: ")) #rate = the interest rate that is charged each year on unpaid principle
years = float(input("Years: ")) #years = the number of years required to repay the loan in full
payment = ((1 + rate)**years * principle * rate)/((1 + rate)**years - 1)
#lines 7-10 print the annual, monthly, and total payments made respectively
print("Annual payment: ${:,.2f}".format(payment))
print("Monthly payment: ${:,.2f}".format(payment/12))
print("Total paid for the life of the loan: ${:,.2f}".format(payment*years))
annualinc = float(input("Annual income: ")) #annualinc = the annual income
#to check if the user needs to refinance or not by comparing their monthly income to their monthly payment
if (annualinc / 12) <= (payment / 12) and rate > .05:
print("You should refinance")
elif (annualinc / 12) <= (payment / 12):
print("You should seek financial counseling")
else:
print("If you make all your payments, your loan will be paid on time.")
I just eliminated the redundant parts and it works on my machine!

Working with commas in output

I'm in an intro programming class and am lost. We've had several labs that required knowledge that we haven't been taught but I've managed to find out what I need on google (as nobody responds to the class message board) but this one has me pretty frustrated. I'll include a pastebin link here: https://pastebin.com/6JBD6NNA
`principal = input()
print('Enter the Principal Value of your investment: $', float(principal))
time = input()
print('\nEnter the Time(in years) you plan to save your investment: ', int(time))
rate = input()
print('\nEnter the Rate (2% = 0.02) you will collect on your investment: ', float(rate))
interest = (float(principal) * float(rate)) * int(time)
final_value = float(principal) + float(interest)
print('\nThe Final Value of your investment will be: $%.2f' % final_value)`
So I need the output of the dollar amounts to have a comma ($27,500.00) but I have no idea how to do this. I've seen a couple of solutions on this site and others but I can't get them to work. PLEASE can someone help me?
In Python 2.7 or above, you can use
print('The Final Value of your investment will be: ${:,.2f}'.format(final_value))
This is documented in PEP 378.
Source: Python Add Comma Into Number String
Here is a working example:
principal = float(input('Enter the Principal Value of your investment: $'))
time = int(input('\nEnter the Time(in years) you plan to save your investment: '))
rate = float(input('\nEnter the Rate (2% = 0.02) you will collect on your investment: '))
interest = principal * rate * time
final_value = principal + interest
print('The Final Value of your investment will be: ${:,.2f}'.format(final_value))
Your last line should be:
print ("\nThe Final Value of your investment will be: ${:,.2f}".format(final_value))

Loan calculator program

So far I have been coding this all week trying to get it to work.
It should come out as this:
Please enter Amount that you would like to borrow(£): 4000
Please enter Duration of the loan(Years):2
Please enter the interest rate (%):6
The total amount of interest for 2 (years) is: £480.00
The total amount of the period for 2 (years) is £4480.00
You will pay £186.67 per month for 24 months.
Do you wish to calculate a new loan payment(Y or N)
Code:
monthlypayment = 0 #Variable
loanamount = 0 #Variable
interestrate = 0 #Variable
numberofpayments = 0 #Variable
loandurationinyears = 0 #Variable
loanamount = input("Please enter the amount that you would like to borrow(£) ")
loandurationinyears = input("How many years will it take you to pay off the loan? ")
interestrate = input("What is the interest rate on the loan? ")
#Convert the strings into floating numbers
loandurationinyears = float(loandurationinyears)
loanamount = float(loanamount)
interestrate = float(interestrate)
#Since payments are once per month, number of payments is number of years for the loan
numberofpayments = loandurationinyears*12
#calculate the monthly payment based on the formula
monthlypayment = (loanamount * interestrate * (1+ interestrate)
* numberofpayments / ((1 + interestrate) * numberofpayments -1))
#Result to the program
print("Your monthly payment will be " + str(monthlypayment))
looks to me like the only thing you're missing in the code above from what you described is a while loop. This will allow your program to calculate the loan and run the program over and over again until the user inputs no, in which case the program exits. all what you have to do is:
YorNo = input("Do you wish to calculate a loan payment")
YorNo.Title()
while YorNo != "n":
#Your code goes here
YorNo = input("Do you wish to calculate a loan payment")
YorNo.Title()
print("Thank you for using the program")
In case you dont understand this, baisically, you type the first 3 lines just before your code. Then you leave an indentation and type your code after them. Once your done, you type in the 3rd and 4th line. Then, simply go back that indentation (to show the program that this isnt part of the loop.) If im not mistaken, the result of this will be:
You will be asked wether you want to calculate a loan
If you answer "y" your code will run and the loan will be calculated and printed to the user
Then you will be asked again. The above will repeat until you input "n"
the N cant be capitalised

Syntax error in Python trying to calculate complicated interest

Here I have the following attemp to calculate complicated interest and mortgage interest for example. However it gives me syntax error on the TotalMonthsMortgage = TotalMonthsMortgage - 1.0 marking the first TotalMonthsMortgage /the one on the left/ and if I quote it it marks the next line AlreadyPaidAmount = AlreadyPaidAmount+TotalAmountMortgage/TotalMonthsMortgage marking the AlreadyPaidAmount on the left. What did I do wrong as I couldn't find mistake myself?
## Complicated interest is the bank interest for example charged for mortgage loans
TotalAmountMortgage = float(raw_input('Enter the total amount of the mortgage to be taken:')) ##this is Principal
TotalYearsMortgage = float(raw_input('Enter the number of total years of the mortgage to be taken:'))
TotalMonthsMortgage = float(TotalYearsMortgage*12.0)
TotalYearsFixedInterest = float(raw_input('Enter the number of years with fixed interest mortgage to be taken:'))
TotalMonthsFixedInterest = 12.0*TotalYearsFixedInterest
FixedInterest = float(raw_input('Enter fixed interest for the mortgage to be taken:'))
FloatingInterest = float(raw_input('Enter floating interest for the mortgage to be taken:'))
PoolInterestPaid = 0.0
MonthlyPayment = 0.0
AlreadyPaidAmount = 0.0
FixedPayment = float(TotalAmountMortgage/TotalMonthsMortgage)
TotalPayment = float
while (TotalMonthsMortgage-TotalMonthsFixedInterest)>0:
MonthlyPayment = FixedPayment+(TotalAmountMortgage-((FixedPayment*TotalMonthsFixedInterest+AlreadyPaidAmount))*FloatingInterest/1200
TotalMonthsMortgage = TotalMonthsMortgage - 1.0
AlreadyPaidAmount = AlreadyPaidAmount+TotalAmountMortgage/TotalMonthsMortgage
TotalPayment = (TotalAmountMortgage*FixedInterest*TotalMonthsFixedInterest)/TotalMonthsMortgage+(TotalAmountMortgage*TotalMonthsFixedInterest)/TotalMonthsMortgage+PoolInterestPaid
print TotalPayment ##This is the total amount to be paid
print (TotalPayment - TotalAmountMortgage) ##This is the amount of intererst to be paid over time
print (TotalPayment - TotalAmountMortgage)/TotalMonthsMortgage ##This is the amount of monthly payment
You have too many parenthesis on the preceding line, you probably wanted one on the end too:
MonthlyPayment = FixedPayment + (
TotalAmountMortgage - (
(FixedPayment * TotalMonthsFixedInterest + AlreadyPaidAmount)
) * FloatingInterest / 1200)
----------------------^
I had to break the line across multiple lines to illustrate the problem, you may want to do the same to keep your code readable at least.
Because Python allows you to break the expression across multiple lines when using parenthesis, Python cannot detect when you forgot a closing parenthesis until the next line of code. The same applies to square brackets ([]), and curly braces ({}).
The rule of thumb therefor is to look at the preceding line too, when you encounter a syntax error.
You are missing a paren on this line:
MonthlyPayment = FixedPayment+(TotalAmountMortgage-((FixedPayment*TotalMonthsFixedInterest+AlreadyPaidAmount))*FloatingInterest/1200
Put a close paren at the end and you should be good to go.

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