Simple question

[Phil Dobbin]

On 15/04/2014 19:30, Robert Kern wrote:

> On 2014-04-15 19:18, Phil Dobbin wrote:
>> Hi, all.
>>
>> I've just started to learn Python (I'm reading Mark Lutz's 'Learning
>> Python' from O'Reilly) & I'm confused as to this part:
>>
>> '>>> 0.1 + 0.1 + 0.1 - 0.3
>> 5.55111.....'
>>
>> Using 'import Decimal' you can get a much closer result i.e.
>> 'Decimal('0.0')'
>>
>> What I'm wondering is why the first calculation that arrives at
>> '5.55111...' is so far out?
> 
> The `...` elides the exponent:
> 
>   >>> 0.1 + 0.1 + 0.1 - 0.3
>   5.551115123125783e-17
> 
> If you copied that verbatim directly out of a book, that's just sloppy
> editing.
> 

No, the ellipses are sloppy editing on my part done purely for brevity.
Unfortunately they elided the relevant part, the meaning of which was,
prior to these conversations, lost on me.

Thanks to all who replied.

Cheers,

  Phil...

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