如何计算复利并使用Django在浏览器中显示？

Question

I am trying to calculate interest using django.

In my models:

class Account(models.Model): principal = models.DecimalField("pricipal", max_digits=15, decimal_places=6) rate = models.DecimalField("interest rate", max_digits=5, decimal_places=5) months = models.IntegerField("number of months", default=0) My goal is to calculate the monthly interest. I need to iterate through each months', write the value to the database, and display the results of the table

How do I calculate principal * rate * months for each month in django? How do I these values in an html table?

Answer 1

This isn't really a Django problem, and your questions is a little unclear. You basically need to apply the compound interest formula in python to an instance of this model:

account = Account.objects.get(pk=<something>)
calc_interest = lambda value: value * account.rate
amount = account.principal
for i in xrange(12):
    interest = calc_interest(amount)
    amount += interest
    print 'month {}: {} ({} interest)'.format(i, amount, interest)

This will give you:

month 0: 1050.0 (50.0 interest)
month 1: 1102.5 (52.5 interest)
month 2: 1157.625 (55.125 interest)
month 3: 1215.50625 (57.88125 interest)
month 4: 1276.2815625 (60.7753125 interest)
month 5: 1340.09564062 (63.814078125 interest)
month 6: 1407.10042266 (67.0047820312 interest)
month 7: 1477.45544379 (70.3550211328 interest)
month 8: 1551.32821598 (73.8727721895 interest)
month 9: 1628.89462678 (77.5664107989 interest)
month 10: 1710.33935812 (81.4447313389 interest)
month 11: 1795.85632602 (85.5169679058 interest)