贷款计算器的Python编码问题

我试图在一个网站上创建一个贷款计算器，但在Python的编码方面遇到了麻烦。代码是：

# user enter the cost of the loan, the interest rate, and
#the number of years for the loan
#Calculate monthly payments with the following formula
# M = L[i(1+i)n] / [(1+i)n-2]
# M = monthly payment
# L = Loan amount
# i = interest rate (for an interest rate of 5%, i = 0.05)
# n = number of payments
#________________________________________________________________________#
#Start of program
#Declare variables

monthlypayment = 0  
loanamount = 0
interestrate = 0
numberofpayments = 0  
loandurationinyears = 0
loanamount = raw_input("Lending Money ")
interestrate = raw_input("Interest Rates are? ")
loandurationinyears = raw_input("Time Duration in Years?")
#Convert the strings into floating numbers so we can use them in the formula
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
payments = loaninyears*12
#calculate the monthly payment based on the formula
payment = amount * interestrate * (7+ interestrate) * payments / ((1 + interestrate) * payments -1)
#Result to the program
print("Payment will be " + st(monthlypayment))

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有经验的人能帮我找到这个编码中的语法或其他逻辑错误吗？

您正在读取以前未声明的变量。 将loaninyears更改为LoanDurationin Years，并将金额更改为loanamount

此外，您在最后一行有一个输入错误，st应该是str

还有一些提示：

首先，你可以做以下事情：

input = float(raw_input("Give me some number"))

这样可以缩短程序的长度

也可以考虑使用更可读的变量命名，例如：

---

loanInYears或loan_in_years

严格遵循评论中的公式，使用Python 2.7运行，但结果不正确

# user enter the cost of the loan, the interest rate, and
#the number of years for the loan
#Calculate monthly payments with the following formula
# M = monthly payment
# L = Loan amount
# i = interest rate (for an interest rate of 5%, i = 0.05)
# n = number of payments

L = input ('loan amount')
i = input ('interest rate')
n = input ('nr of payments')

M = L*(i*(1+i)*n) / ((1+i)*n-2)

print (M)

我认为你应该首先修正你的公式，除了编码错误。 我特别想念12号，因为你的利息是每年的，但你的付款是每月的

[编辑]

看看乔希的答案：

也许可以使用不同的视频教程，因为这一教程似乎会让很多人陷入困境

---

提示：如果您有非常长的可变名称，您可以在其中添加一些下划线，但贷款年数未定义。您将它乘以12。

print（“付款将是”+st（monthlypayment））

我认为

st

应该是

str

这里的金额可能应该是loanamount，并且您从来没有给monthlypayment一个0以外的值