YouTube Python Mortgage Calculator（ゼロからヒーロー）

Question

これは私がモーゲージを計算するためにYouTubeからPythonプログラミングチュートリアルでゼロからヒーローを外したコードです。私はこのコードが他の支払い計算機を使っているのと同じ回答を私に与えていない理由を理解しようとしています。私はのために同様の[投稿の] [1]の答えを使用

# M = L[i(1+i)n]/[(1+i)n-1] 


#Declare and initialize the variables 
monthlyPayment = 0 
loanAmount = 0 
interestRate = 0 
numberOfPayments = 0 
loanDurationInYears = 0 

#Ask the user for the values needed to calculate the monthly payments 
strLoanAmount = input("How much money will you borrow? ") 
strInterestRate = input("What is the interest rate on the loan? ") 
strLoanDurationInYears = input("How many years will it take you to pay off the loan? ") 

#Convert the strings into floating numbers so we can use them in the formula 
loanDurationInYears = float(strLoanDurationInYears) 
loanAmount = float(strLoanAmount) 
interestRate = float(strInterestRate) 

#Since payments are once per month, number of payments is number of years for the loan * 12 
numberOfPayments = loanDurationInYears*12 

#Calculate the monthly payment based on the formula 
monthlyPayment = loanAmount * interestRate * (1+ interestRate) * numberOfPayments \ 
    /((1 + interestRate) * numberOfPayments -1) 

#provide the result to the user 
print("Your monthly payment will be " + str(monthlyPayment)) 

#Extra credit 
print("Your monthly payment will be $%.2f" % monthlyPayment) 

Answer 1

...私は私に正しい答えを与える他のコードがある知っているが、私はこの1つが悪いのかを把握しようとしています次のコード：

# M = L[i(1+i)n]/[(1+i)n-1] 


#Declare and initialize the variables 
monthlyPayment = 0.0 
loanAmount = 0.0 
interestRate = 0.0 
numberOfPayments = 0.0 
loanDurationInYears = 0.0 

#Ask the user for the values needed to calculate the monthly payments 
strLoanAmount = input("How much money will you borrow? ") 
strInterestRate = input("What is the interest rate on the loan? ") 
strLoanDurationInYears = input("How many years will it take you to pay off the loan? ") 

#Convert the strings into floating numbers so we can use them in the formula 
loanDurationInYears = float(strLoanDurationInYears) 
loanAmount = float(strLoanAmount) 
interestRate = float(strInterestRate)/100/12 

#Since payments are once per month, number of payments is number of years for the loan * 12 
numberOfPayments = float(loanDurationInYears)*12 

#Calculate the monthly payment based on the formula 
monthlyPayment = loanAmount * (interestRate * (1 + interestRate) ** numberOfPayments)/((1 + interestRate) ** numberOfPayments - 1) 

#provide the result to the user 
print("Your monthly payment will be " + str(monthlyPayment)) 

#Extra credit 
print("Your monthly payment will be $%.2f" % monthlyPayment) 


    [1]: http://stackoverflow.com/questions/29804843/formula-for-calculating-interest-python