From: Logan Capaldo <logancapaldo@...>
Date: 2006-04-02T08:50:07+09:00
Subject: Re: Ruby way to sum digits


On Apr 1, 2006, at 9:29 AM, James Edward Gray II wrote:

> On Apr 1, 2006, at 7:22 AM, Marcus Lunzenauer wrote:
>
>> Hello!
>>
>> To sum the digits of an Integer I have got
>>
>> class Integer
>>   def sum_digits()
>>     sum = 0
>>     n = self
>>     begin sum += n % 10; n /= 10 end while n > 0
>>     sum
>>   end
>> end
>>
>>
>> Is there a more Ruby Way to do this? The above method smells of  
>> Java, doesn't it?
>
> Here is what I thought of when reading this:
>
> >> class Integer
> >>   def sum_digits
> >>     to_s.split("").inject(0) { |sum, n| sum + n.to_i }
> >>   end
> >> end
> => nil
> >> 1234.sum_digits
> => 10
>
> Hope that helps.
>
> James Edward Gray II
>

num_s =  num.to_s
(0...(num_s.length)).inject(0) { |s, i| s += (num_s[i]  - ?0) }

Just to increase confusion and to rely on the properties of ASCII