# [Tutor] base n fractional

Chris Castillo ctcast at gmail.com
Mon Apr 6 02:17:20 CEST 2009

well i want to use a for loop to work from the right most digit to the left
most digit at a negative 1 increment. For each digit i want to divide it by
1/base and add the next digit. Then I need to take that sum and multiply it
by 1/b to get the decimal equivalent

so when I say that to myself i see:
number = 234
mysum = 0
for digit in range(len(number) -1, -1, -1):
mysum = (mysum) * (1/base) + int(number[digit])

On Sun, Apr 5, 2009 at 6:25 PM, Alan Gauld <alan.gauld at btinternet.com>wrote:

>
> "Chris Castillo" <ctcast at gmail.com> wrote
>
>  I need some help converting the fractional (right side of the decimal) to
>> base 10.
>> I have this but it doesn't work
>>
>
> Frankly, based on your algorithm, I'm not sure what exactly you want
> to do but taking the above statement as a starting point
>
> I'd convert the fractional part into an integer then divide by 10**(len(n))
>
> Something like:
>
> n = raw_input('????')   # say  n ->1.234
> d,f = n.split('.')               # so d -> '1', f -> '234'
> result = int(f)/(10**len(f))         # result = 234/10**3 = 234/1000 =
> 0.234
>
> Or you could just add a dot back on and convert to float:
>
> f = float('.'+f)    # float('.234') -> 0.234
>
>  for digit in range(len(myfrac) -1, -1, -1):
>>   mydecfrac = mydecfrac + int(myfrac[digit])
>>   mydecfrac = mydecfrac / base
>>
>
> This just confused me.
> I think this might do what you are trying to do:
>
> for digit in reversed(list('234')):
>    mydecfrac = (mydecfrac + int(digit)) / base
>
> But that doesn't seem to do what I think you wanted?
>
>
> --
> Alan G
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/l2p/
>
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>
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