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To: python-list@python.org
From: Mark Lawrence <breamoreboy@yahoo.co.uk>
Subject: Re: What is considered an "advanced" topic in Python?
Date: Mon, 01 Jun 2015 11:34:08 +0100
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On 01/06/2015 08:58, Laura Creighton wrote:
> If you are giving a talk about Decimal -- and trying to stamp out the
> inappropriate use of floats you have to first inform people that
> what they learned as 'decimals' as children was not floating point,
> despite the fact that we write them the same way.
>
> If I ever get the time machine, I am going back in time and demand that
> floating point numbers be expressed as 12345:678 instead of 12345.678
> because it would save so much trouble.  Never has the adage 'It's not
> what you don't know, that bites you.  It's what you know that ain't so.'
> been more apt.
>
> I have done much better in speaking about this topic to a bunch of
> incredulous people if you next explain that scientists really don't
> care about accuracy in their calculations.  (This will surprise them).
> Most scentific calculations have some real world measurement in them,
> and for most real world measurements, if you are getting even 5 digits
> of precision, you are doing really, really, well.  This means that
> scientists are going to be throwing away all the extra digits they get
> out a a floating point representation, so they don't have to care how
> accurate they are.  As long as their results are good in the first 5,
> it won't matter.  (Depending on time constraints, a review of
> significant figures -- what they are and what they mean is good here.)
>
> It is really hard to get the concept of Decimal across to people who
> already have that concept in their mind, but think it is called Float.
> You have to first teach them that they don't know anything about Float
> and get them to reboot their brains before you can install this new
> knowledge.  Otherwise their brains will just overwrite your new knowledge
> with 'ah, just use a Float' as soon as you stop speaking.  Same day,
> even.
>
> Laura
>

In the wonderful world of numbers I believe that things are looking up. 
  I don't recall a new issue on the bug tracker for several months along 
the lines of "Python can't do arithmetic properly".

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence