Working with decimals

[Joel Goldstick]

On Sat, Aug 23, 2014 at 1:47 PM, Seymore4Head
<Seymore4Head at hotmail.invalid> wrote:
> I am trying to do this example:
> http://openbookproject.net/pybiblio/practice/wilson/loan.php
> The instructions warn that floating point math can get messy so I
> cheated a little bit to get me going.
>
> I made my program work by using numbers that wouldn't get messy.
> Instead of using 6% interest I used 10 and instead of using 12 months,
> I used 10.
>
> I managed to get it working and formatted just like they wanted it,
> but now I want to try to use any numbers.  It has been hard to figure
> out which method to use.
>
You need to learn about string formatting.  Here is a good link:
http://mkaz.com/2012/10/10/python-string-format/

> Here is the working program.
>
> import sys
> count = 0
> payment = 0
> borrowed = 100
> rate = 10
> term = 10
> interest=borrowed*rate*.01     #(*1)
> balance = borrowed + interest
> print ("Loan calculator")
> print ("")
> print ("Amount borrowed: ", borrowed)
> print ("Interest rate: ", rate)
> print ("Term: (months)", term)
> print ("")
> print ("Amount borrowed:" , borrowed)
> print ("Total interest paid:" , interest)
> print ("")
> print ("")
> print ("            Amount      Remaining")
> print ("Pymt#        Paid        Balance")
> print ("-----       ------       ----------")
> while count <=term:
>
>
>     print (repr(count).rjust(3), repr(payment).rjust(13),
> repr(balance).rjust(14))
>
>
I don't understand why you are using repr(..)  It is not necessary.

>     payment = (borrowed + interest)/term
>     balance = balance - payment
>     count = count + 1
>
> What should I use to make the formatting come out correctly when the
> program prints "payment" and "balance" using decimal format?
>
> If you change the "rate" from 10 to 6 and the "term" from 10 to 12,
> the screen gets very messy.
>
> Anyone care to suggest what method to use to fix the decimal format?
> --
> https://mail.python.org/mailman/listinfo/python-list



-- 
Joel Goldstick
http://joelgoldstick.com