Loan calculator program - python

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

Related

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!

How do you round a string in Python?

I am new to Python and a student, my college has chosen the worst book on earth for our course. I cannot find examples of any concepts, so I apologize in advance as I know these concepts are very basic. I hope you can help me.
I need to know how to use the round feature in a string. I find examples but they do not show the string, just simple numbers.
Here is what we are supposed to get as an output:
Enter the gross income: 12345.67
Enter the number of dependents: 1
The income tax is $-130.87 <---- this is what we are supposed to figure out
Here is the coding we are given to alter:
TAX_RATE = 0.20
STANDARD_DEDUCTION = 10000.0
DEPENDENT_DEDUCTION = 3000.0
# Request the inputs
grossIncome = float(input("Enter the gross income: "))
numDependents = int(input("Enter the number of dependents: "))
# Compute the income tax
taxableIncome = grossIncome - STANDARD_DEDUCTION - \
DEPENDENT_DEDUCTION * numDependents
incomeTax = taxableIncome * TAX_RATE
# Display the income tax
print("The income tax is $" + str(incomeTax))
As I do not have an NUMBER to plug into the formula - I have to figure out how to use "incomeTax" - I have no idea how to do this. THe book doesnt explain it. Help?
You can use format strings:
print("The income tax is ${:.2f}".format(incomeTax))
If you are using Python 3.6+, you can also use f-strings:
print(f"The income tax is ${incomeTax:.2f}")
You can round just before making it a string:
print("The income tax is $" + str(round(incomeTax,2)))
Output:
Enter the gross income: 12345.67
Enter the number of dependents: 1
The income tax is $-130.87
Im a student as well, with the same dumb book and HW.
I tried the above
str(round(incomeTax,2))
and it didn’t work. Maybe I typed something wrong. After playing around I found this to work
# Display the income tax
incomeTax = round(incomeTax,2)
print(“The income tax is $” + str(incomeTax))
I hope this helps some other poor soul searching the web for an answer!

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))

Python won't print expression

So, I'm kind of new to programming and have been trying Python. I'm doing a really simple program that converts usd to euroes.
This is the text of the problem that I'm trying to solve
You are going to travel to France. You will need to convert dollars to euros (the
currency of the European Union). There are two currency exchange booths. Each has
a display that shows CR: their conversion rate as euros per dollar and their fee as a
percentage. The fee is taken before your money is converted. Which booth will give
you the most euros for your dollars, how many euros, and how much is the difference.
Example 1:
Dollars: 200
CR1: 0.78
Fee: 1 (amount 152.88 euros)
CR2: 0.80
Fee: 3 (amount 155.2 euros)
Answer: 2 is the best; difference is 2.32 euros; 155.2 euros
And here is my code
from __future__ import division
usd = int(input("How much in USD? "))
cr1 = int(input("What is the convertion rate of the first one? "))
fee1 = int(input("What is the fee of the first one? "))
cr2 = int(input("What is the convertion rate of the second one? "))
fee2 = int(input("What is the fee of the second one? "))
def convertion (usd, cr, fee):
usdwfee = usd - fee
convert = usdwfee * cr
return convert
first = convertion(usd, cr1, fee1)
second = convertion(usd, cr2, fee2)
fs = first - second
sf = second - first
def ifstatements (first,second,fs,sf):
if first < second:
print "1 is the best; difference is ",fs," euroes. 2 converts to ",first," euroes."
elif first > second:
print "2 is the best; difference is",sf," euroes. 2 converts to", second," euroes."
ifstatements(first, second, fs, sf)
The problem is that when I run the program it won't print out. It just takes my input and doesn't output anything.
Check your logic more.
cr1 = int(input("What is the convertion rate of the first one? "))
Your conversion rate is in int. As in Integer which means it can't have a floating point (a decimal "CR1: 0.78" from your example). Your cr1 will become 0 if you cast it into an int. Also change your dollar and fees to accept floats too since I'm assuming you want to deal with cents too
So change:
usd = float(input("How much in USD? "))
cr1 = float(input("What is the convertion rate of the first one? "))
fee1 = float(input("What is the fee of the first one? "))
cr2 = float(input("What is the convertion rate of the second one? "))
fee2 = float(input("What is the fee of the second one? "))
And it should work.

Python car sales code issue

Ok so, I have an assignment to make a carsales program which is suppose to calculate how much the salesperson will make in a week. I already know how much all the cars sell for and how much commission he makes. Here is my code:
def main():
print ('This program will compute the comission earned for the week based on your sales for the week.')
car_number = float(input('Enter number of cars sold :'))
def calculate_total(car_number,price,commission_rate):
price = 32,500.00
commission_rate = .025
calculate_total = car_number * price * commission_rate
return calculate_total(car_number)
print('The weekly gross pay is $',calculate_total)
main()
The program isn't working for some reason but I decided to submit it to my professor anyway. He then replied by saying that I wasn't asked to create a new function and that I have to delete it and work just in main. Can someone please tell me what this means?
Two things:
'Working in main' as your professor said means that you don't define any functions. All your code just sits in the file, without any def ... statements. I know that's probably not clear. Here's an example:
import os
print "Your current working directory is:"
print os.getcwd()
This kind of programming has more the feel of a 'script' - you're not defining parts of the program that you're going to use more than once, and you're not taking the trouble to break down what the program does into single-purpose functions.
Second, you've entered price in such a way that Python thinks you're creating a tuple of numbers instead of a single value.
price = 32,500.00 is interpreted by Python as creating a tuple, with values 32 and 500.00 in it. What you actually want is: price = 32500.00.
I broke down and completed the process for you.
print ('This program will compute the comission earned for the week based on your sales for the week.')
car_number = float(input('Enter number of cars sold :'))
price = 32500.00
commission_rate = .025
calculate_total = car_number * price * commission_rate
print('The weekly gross pay is $',calculate_total)
Sorry i did not saw the complete question before but anyway this is the correct answer without a function
The keywords try and except are for error handling. If you give as input something invalid let's say a letter instead of number will throw a message
(Could not convert input data to a float.)
def main():
print ('This program will compute the comission earned for the week based on your sales for the week.')
try:
#before: car_number = float(raw_input('Enter number of cars sold :'))
car_number = float(input('Enter number of cars sold :'))
except ValueError:
#before: print 'Could not convert input data to a float.'
print('Could not convert input data to a float.')
print('The weekly gross pay is ${}'.format(car_number * 32500.00 * 0.025 )))
main()
If you don't even want main() function here is the answer:
print ('This program will compute the comission earned for the week based on your sales for the week.')
try:
car_number = float(input('Enter number of cars sold :'))
except ValueError:
print('Could not convert input data to a float.')
print('The weekly gross pay is ${}'.format(car_number * 32500.00 * 0.025 )))

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