Python简单利息计算

Question

我正在计算每月要付多少钱才能在12个月内还清贷款。使用10美元作为增量。在

Payment = 0
balance = float (1200)
interest = float (0.18)
MonthlyInt = interest/12.0

while balance > 0 :

    Payment = Payment + 10
    month = 0
    while month < 12 and balance > 0:
        IntPay = balance* MonthlyInt
        balance += IntPay
        balance -= Payment
        month += 1
print Payment

正确答案应该是110，为什么我得到60？在

Answer 1

这是另一种方法。我试着在麻省理工学院的edx课程中使用Brians的例子，但没能让它在所有情况下都起作用。在

我就是这样做的。在

def lowestpayment(x,y):
""" x = total balance due
    y = annual interest rate 
    Returns min payment needed to pay off debt in 1 year
"""
month = 0
balance = x
annualInterestRate = y
payment = 0
while balance > 0 and month <= 12:
    month = 0
    balance = x
    payment += 10
    balance = balance - payment
    monthlyint = balance*annualInterestRate/12
    balance += monthlyint
    month += 1
    if balance+(balance*annualInterestRate/12)*11-payment*12 <= 0:
        return payment


print("Lowest Payment: ",lowestpayment(35,0.25))

Answer 2

产生差异的主要原因是：

• 在再次循环12个月之前，余额应重置为1200
• 在计算利息之前，这笔款项应该从余额中扣除

一些更小的python功能是：

• float()不需要围绕0.18这样的数字，它已经是一个浮点数了
• 1200.表示该数字是一个浮点数，因此不需要float()

那么，考虑一下这些事情：

Payment = 0
interest = 0.18
MonthlyInt = interest/12.0
balance = 1200.

while balance > 0 :

    Payment = Payment + 10
    month = 0
    balance = 1200.
    while month < 12 and balance > 0:
        balance -= Payment
        IntPay = balance* MonthlyInt
        balance += IntPay
        month += 1
print(Payment)

给出110的结果。在