贷款计算器的 Python 编码问题答案

【问题标题】：Python Coding Issue for Loan Calculator贷款计算器的 Python 编码问题
【发布时间】：2017-06-14 16:26:46
【问题描述】：

我正在尝试在网站上创建一个贷款计算器，但在 Python 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))

有经验的人可以帮我解决这个编码中的语法或其他逻辑错误吗？

【问题讨论】：

loaninyears 未定义。你将它乘以 12。
print("Payment will be " + st(monthlypayment)) 我认为st 应该是str
amount 应该是 loanamount 并且你永远不会给monthlypayment 一个非0 的值

标签： python calculator

【解决方案1】：

您正在读取之前未声明的变量。将 loaninyears 更改为 loandurationinyears 并将 amount 更改为 loanamount。

另外你在最后一行有错字，st 应该是 str

还有一些提示：

首先，您可以执行以下操作：

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

这样可以缩短程序的长度。

另外你可能想考虑使用更易读的变量命名，例如：

loanInYears 或 loan_in_years

【讨论】：

【解决方案2】：

密切遵循 cmets 中的公式，并使用 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)

我认为你应该先修正你的公式，除了编码错误。具体来说，我在某处错过了数字 12，因为您的利息是每年，但您的付款是每月。

[编辑]

在这里看看乔希的答案：

Formula for calculating interest Python

也许使用不同的视频教程，因为这似乎给很多人带来了麻烦。

提示：如果你有很长的变量名 you_may_place_some_underscores_in_them

【讨论】：