Working with decimals

[Joel Goldstick]

On Sat, Aug 23, 2014 at 3:07 PM, Seymore4Head
<Seymore4Head at hotmail.invalid> wrote:
> On Sat, 23 Aug 2014 14:21:03 -0400, Joel Goldstick
> <joel.goldstick at gmail.com> wrote:
>
>>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/
>>
> Thanks.  I will give that a try.
>
>>> 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.
>>
> Would you please change the line to something you feel that is more
> appropriate?  That was the first command I stumbled on that I could
> use to get the column spacing correctly.
> I have contacted my local library to get a couple of books on Python,
> but at the moment all I have is the web.
>
> Funny, I though using the web would be better than a book.  I don't
> think so anymore.  Using the web, it is hard to find square one
> tutorial text.
>

You should go to python.org and take a look at the tutorial.  There
are lots of references to other sites there as well
>
>>>     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
>
> I would rather just use Usenet for the moment.  Until the group gets
> tired of nursing the rookie.
> --
> https://mail.python.org/mailman/listinfo/python-list



-- 
Joel Goldstick
http://joelgoldstick.com