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From: shot@hot.pl (Shot (Piotr Szotkowski))
Subject: [sup-talk] Util - Fixnum num_digits is wrong
Date: Mon, 3 Dec 2007 11:52:10 +0100	[thread overview]
Message-ID: <20071203105210.GO1974@durance.shot.pl> (raw)
In-Reply-To: <1196670157-sup-6857@silver>

Ian Taylor:

>  class Fixnum
>    def num_digits base=10
>      return 1 if self == 0
> -    1 + (Math.log(self) / Math.log(10)).floor
> +    1 + (Math.log(self) / Math.log(base)).floor
>    end

Math.log and Float#/ returning Floats means the above
approach is prone to the IEEE 754 representation inaccuracy.

Wouldn?t the below make more sense?

class Fixnum
  def num_digits base = 10
    to_s(base).size
  end
end

-- Shot
-- 
> Who wants to recommend a Usenet reader for little ol' me?
I recommend Garrett Morris, particularly if you're hard-of-hearing.
      -- jennifer friedoff and Joseph Nebus, rec.arts.tv.mst3k.misc
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  reply	other threads:[~2007-12-03 10:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-03  8:25 Ian Taylor
2007-12-03 10:52 ` Shot (Piotr Szotkowski) [this message]
2007-12-08 22:13   ` William Morgan

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