Python面向对象编程实训
作者：互联网
按揭贷款——定义抽象类
def findPayment(loan, r, m):
#********** Begin *********#
# 请在下面编写代码
up = r*(1+r)**m
dn = (1+r)**m-1
return loan*(up/dn)
# 请不要修改下面的代码
#********** End *********#
class Mortgage(object):
def __init__(self, loan, annRate, months):
#********** Begin *********#
# 请在下面编写代码
self.loan = loan
self.annRate = annRate
self.months = months
self.rate = self.annRate/12/100
self.paid = [0.0]
self.owed = [loan]
self.payment = findPayment(loan,self.rate,months)
# 请不要修改下面的代码
#********** End *********#
self.legend = None
def makePayment(self):
#********** Begin *********#
# 请在下面编写代码
self.paid.append(self.payment)
reduction = self.payment - self.owed[-1] * self.rate
self.owed.append(self.owed[-1] - reduction)
# 请不要修改下面的代码
#********** End *********#
def getTotalPaid(self):
#********** Begin *********#
# 请在下面编写代码
return sum(self.paid)
# 请不要修改下面的代码
#********** End *********#
def __str__(self):
return 'The Mortgage is {self.legend}, Loan is {self.loan}, Months is {self.months}, Rate is {self.rate:.2f}, Monthly payment is {self.payment:.2f}'.format(self=self)
if __name__=="__main__":
print(Mortgage(100000, 6.5, 36))
print(Mortgage(100000, 6.5, 120))
三种贷款方式建模
def findPayment(loan, r, m):
return loan * ((r * (1 + r) ** m) / ((1 + r) ** m - 1))
class Mortgage(object):
def __init__(self, loan, annRate, months):
self.loan = loan
self.rate = annRate / 1200.0
self.months = months
self.paid = [0.0]
self.owed = [loan]
self.payment = findPayment(loan, self.rate, self.months)
self.legend = None
def makePayment(self):
self.paid.append(self.payment)
reduction = self.payment - self.owed[-1] * self.rate
self.owed.append(self.owed[-1] - reduction)
def getTotalPaid(self):
return sum(self.paid)
def __str__(self):
return str(self.legend)
class Fixed(Mortgage):
def __init__(self, loan, r, months):
# 请在此添加代码，补全函数__init__
#********** Begin *********#
self.loan = loan
self.r = r
self.months = months
#********** End *********#
self.legend = 'Fixed, ' + str(r) + '%, for ' + str(months) + ' months'
class FixedWithPoints(Mortgage):
def __init__(self, loan, r, months, pts):
# 请在此添加代码，补全函数__init__
#********** Begin *********#
self.loan = loan
self.pts = pts
self.months = months
#********** End *********#
self.legend = 'Fixed, ' + str(r) + '%, ' + str(pts) + ' points, for ' + str(months) + ' months'
class TwoRate(Mortgage):
def __init__(self, loan, r, months, teaserRate, teaserMonths):
# 请在此添加代码，补全函数__init__
#********** Begin *********#
self.loan = loan
self.r = r
self.months = months
self.teaserRate = teaserRate
self.teaserMonths = teaserMonths
#********** End *********#
self.legend = str(teaserRate)\
+ '% for ' + str(self.teaserMonths)\
+ ' months, \n then ' + str(r) + '%, for ' + str(months) + ' months'
def makePayment(self):
# 请在此添加代码，补全函数makePayment
#********** Begin *********#
if len(self.paid) == self.teaserMonths + 1:
self.rate = self.nextRate
self.payment = findPayment(self.owed[-1], self.rate, self.months - self.teaserMonths)
#********** End *********#
Mortgage.makePayment(self)
if __name__=="__main__":
print(Fixed(100000, 6.5, 36))
print(Fixed(100000, 6.5, 120))
print(FixedWithPoints(100000, 6.5, 36, 20))
print(FixedWithPoints(100000, 6.5, 120, 20))
print(TwoRate(100000, 9.0, 36, 4.8, 12))
print(TwoRate(100000, 7.0, 120, 4.8, 36))
比较各种贷款的利弊
def findPayment(loan, r, m):
return loan * ((r * (1 + r) ** m) / ((1 + r) ** m - 1))
class Mortgage(object):
def __init__(self, loan, annRate, months):
self.loan = loan
self.rate = annRate / 1200.0
self.months = months
self.paid = [0.0]
self.owed = [loan]
self.payment = findPayment(loan, self.rate, self.months)
self.legend = None
def makePayment(self):
self.paid.append(self.payment)
reduction = self.payment - self.owed[-1] * self.rate
self.owed.append(self.owed[-1] - reduction)
def getTotalPaid(self):
return sum(self.paid)
def __str__(self):
return str(self.legend)
class Fixed(Mortgage):
def __init__(self, loan, r, months):
Mortgage.__init__(self, loan, r, months)
self.legend = 'Fixed, ' + str(r) + '%, for ' + str(months) + ' months'
class FixedWithPoints(Mortgage):
def __init__(self, loan, r, months, pts):
Mortgage.__init__(self, loan, r, months)
self.pts = pts
self.paid = [loan * (pts / 100.0)]
self.legend = 'Fixed, ' + str(r) + '%, ' + str(pts) + ' points, for ' + str(months) + ' months'
class TwoRate(Mortgage):
def __init__(self, loan, r, months, teaserRate, teaserMonths):
Mortgage.__init__(self, loan, teaserRate, months)
self.teaserMonths = teaserMonths
self.teaserRate = teaserRate/1200
self.nextRate = r / 1200.0
self.legend = str(teaserRate)\
+ '% for ' + str(self.teaserMonths)\
+ ' months, \n then ' + str(r) + '%, for ' + str(months) + ' months'
def makePayment(self):
if len(self.paid) == self.teaserMonths + 1:
self.rate = self.nextRate
self.payment = findPayment(self.owed[-1], self.rate, self.months - self.teaserMonths)
Mortgage.makePayment(self)
def compareMortgages(amt, years, fixedRate, pts, ptsRate, varRate1, varRate2, varMonths):
# 请在此添加代码，补全函数compareMortgages
#********** Begin *********#
totMonths = years * 12
fixed1 = Fixed(amt, fixedRate, totMonths)
fixed2 = FixedWithPoints(amt, ptsRate, totMonths, pts)
twoRate = TwoRate(amt, varRate2, totMonths, varRate1, varMonths)
morts = [fixed1, fixed2, twoRate]
#********** End *********#
for m in range(totMonths):
# 请在此添加代码，补全函数compareMortgages
#********** Begin *********#
for mort in morts:
mort.makePayment()
#********** End *********#
for m in morts:
print(m)
print('Loan ' + str(amt) + ' Total payments = ' + str(int(m.getTotalPaid())))
if __name__=="__main__":
compareMortgages(200000, 30, 7, 3.25, 5, 4.5, 9.5, 48)
print('*'*40)
compareMortgages(1000000, 30, 7, 20, 5, 4.5, 9.5, 48)
print('*' * 40)
compareMortgages(500000, 10, 7, 20, 5, 4.5, 9.5, 48)
标签：__,str,Python,self,months,实训,面向对象编程,loan,def 来源： https://blog.csdn.net/qq_43844044/article/details/110094976