From: Robert Klemme <shortcutter@...>
Date: 2010-07-22T02:45:07+09:00
Subject: Re: How to check if x is a multiple of y

On 21.07.2010 13:20, Xavier Noria wrote:
> On Wednesday, July 21, 2010, Robert Klemme<shortcutter@googlemail.com>  wrote:
>> 2010/7/21 Xavier Noria<fxn@hashref.com>:
>>> On Wed, Jul 21, 2010 at 12:12 PM, Tom Ha<tom999@gmx.net>  wrote:
>>>
>>>> what's the most simple solution in Ruby to check if value x is a
>>>> multiple of y?
>>>
>>> That's typically done with the modulus operator, Active Support
>>> defines it this way
>>>
>>>     class Integer
>>>       # Check whether the integer is evenly divisible by the argument.
>>>       def multiple_of?(number)
>>>         number != 0 ? self % number == 0 : zero?
>>>       end
>>>     end
>>>
>>> It is special-cased because you can't do modulus 0.
>>
>> I see a benchmark lurking: that version vs. this one.
>>
>> class Integer
>>    def multiple_off? number
>>      zero? || self % number == 0
>>    end
>> end
>>
>> :-)
>
> But that one is not well-defined for 1.multiple_of?(0) :-)

There you see why posting in a hurry is a bad idea.  Thanks for catching 
that.

Cheers

	robert

-- 
remember.guy do |as, often| as.you_can - without end
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