[Python-Dev] Re: Decimal data type issues

Jewett, Jim J jim.jewett at eds.com
Mon Apr 19 14:39:22 EDT 2004

[Kevin Jacobs]
#-   Decimal('2.4000', precision=2, scale=1) == Decimal('2.4')
#-   Decimal('2.4', precision=5, scale=4) == Decimal('2.4000')
#- Remember, these literals are frequently coming from an 
#- external source that must be constrained to a given schema.

> I like it a lot, but not for Decimal.

This is another face of "what do do with float"

Just because your default context has n digits of precision
doesn't mean that all your input will.

If my input has 2.4000 (but the extra zeros were measured)
then I want to keep that information.

If my input has 2.4 (and I didn't measure beyond those digits)
I want to know that for error analysis.

If my input has 1.1 (only measured to two digits) but my 
context is 25, I don't want to assume that the machine's
float-rounding is correct; the fairest "I don't know" 
estimate is still zero, even out to digit 100.


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