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Re: Significant figures calculation

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Date Mon, 27 Jun 2011 13:53:17 -0700
From Ethan Furman <ethan@stoneleaf.us>
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To Harold <dadapapa@googlemail.com>
Subject Re: Significant figures calculation
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Harold wrote:
> On Jun 25, 9:04 pm, Chris Torek <nos...@torek.net> wrote:
>>> I'm curious.  Is there a way to get the number of significant digits
>>> for a particular Decimal instance?
>> Yes:
>>
>> def sigdig(x):
>>     "return the number of significant digits in x"
>>     return len(x.as_tuple()[1])
> 
> Great, Chris, this is (almost) exactly what I needed.
> To make it work for numbers like 1200, that have four digits but only
> two of them being significant, I changed your snippet to the
> following:
> 
> class Empirical(Decimal) :
>     @property
>     def significance(self) :
>         t = self.as_tuple()
>         if t[2] < 0 :
>             return len(t[1])
>         else :
>             return len(''.join(map(str,t[1])).rstrip('0'))
> 
> 
>>>> Empirical('1200.').significance
> 2
>>>> Empirical('1200.0').significance
> 5

What about when 1200 is actually 4 significant digits? Or 3?

~Ethan~

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Thread

Significant figures calculation Harold <dadapapa@googlemail.com> - 2011-06-24 13:05 -0700
  Re: Significant figures calculation Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-24 20:46 +0000
    Re: Significant figures calculation Jerry Hill <malaclypse2@gmail.com> - 2011-06-24 16:58 -0400
      Re: Significant figures calculation steve+comp.lang.python@pearwood.info - 2011-06-25 10:31 +1000
      Re: Significant figures calculation Chris Torek <nospam@torek.net> - 2011-06-25 19:04 +0000
        Re: Significant figures calculation Harold <dadapapa@googlemail.com> - 2011-06-26 08:35 -0700
          Re: Significant figures calculation Dave Angel <davea@ieee.org> - 2011-06-27 08:04 -0400
        Re: Significant figures calculation Harold <dadapapa@googlemail.com> - 2011-06-27 06:40 -0700
          Re: Significant figures calculation Ethan Furman <ethan@stoneleaf.us> - 2011-06-27 13:53 -0700
            Re: Significant figures calculation Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-28 12:56 +1000
              Re: Significant figures calculation Chris Angelico <rosuav@gmail.com> - 2011-06-28 13:16 +1000
                Re: Significant figures calculation Erik Max Francis <max@alcyone.com> - 2011-06-27 20:45 -0700
                Re: Significant figures calculation Mel <mwilson@the-wire.com> - 2011-06-28 07:47 -0400
                Re: Significant figures calculation Chris Angelico <rosuav@gmail.com> - 2011-06-28 21:57 +1000
                Re: Significant figures calculation Erik Max Francis <max@alcyone.com> - 2011-06-28 11:54 -0700
                Re: Significant figures calculation Mel <mwilson@the-wire.com> - 2011-06-28 16:47 -0400
                Re: Significant figures calculation Erik Max Francis <max@alcyone.com> - 2011-06-28 14:01 -0700
                Re: Significant figures calculation Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-06-28 18:35 +1000
                Re: Significant figures calculation Erik Max Francis <max@alcyone.com> - 2011-06-28 11:59 -0700
              Re: Significant figures calculation Erik Max Francis <max@alcyone.com> - 2011-06-27 20:49 -0700
          Re: Significant figures calculation Ethan Furman <ethan@stoneleaf.us> - 2011-06-27 15:58 -0700
    Re: Significant figures calculation Harold <dadapapa@googlemail.com> - 2011-06-24 18:50 -0700

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