[Python-Dev] Re: Decimal data type issues
Jewett, Jim J
jim.jewett at eds.com
Mon Apr 19 14:39:22 EDT 2004
#- 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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