From: Logan Capaldo <logancapaldo@...>
Date: 2006-06-04T09:12:32+09:00
Subject: Re: Where can one find examples of masterful Ruby code?


On Jun 3, 2006, at 6:39 PM, Christer Nilsson wrote:

> Logan Capaldo wrote:
>> On Jun 3, 2006, at 4:48 PM, Alder Green wrote:
>>
>>> For example: check if integer i is a power of 2, with an  
>>> expression no
>>> more than 13 characters long.
>>>
>>> Solution: (i & (i - 1))
>>
>> I'm confused.
>>
>>
>> irb(main):001:0> i = 9
>> => 9
>> irb(main):002:0> (i & (i - 1))
>> => 8
>>
>> So 9 is a power of 2?
>>
>> As far as 13 characters goes
>>
>> (i % 2).zero?
>>
>> is _exactly_ 13 characters and it gives a true or false answer
>> instead of zero of something else.
>
> Actually you have to compare with zero to get the expected result as
> a previous poster posted:
>
>   def powerof2?( i )
>     (i&(i-1))==0
>   end
>
> (i&(i-1))==0 counts to twelve characters.
>
> i%2 determines odd or even.
>
> powerof2?(9) => false
> powerof2?(16) => true
>
>
> /christer
>
> -- 
> Posted via http://www.ruby-forum.com/.
>

I was trying to make a point. Unfortunately for my point making, I  
misunderstood the function. I was trying to come up with a reasoned  
argument for this but I can't, and my example sucked. So I just want  
to say "(n & (n - 1)) is icky."