[Python-Dev] Change in Python 3's "round" behavior

Greg Ewing greg.ewing at canterbury.ac.nz
Sun Sep 30 18:04:31 EDT 2018

Steven D'Aprano wrote:
> (It's also called Dutch Rounding.)

Oh, so *that's* why Python does it! Fair enough. :-)

> Similarly for differences. If you perform many subtractions (let's say 
> you are paying off a loan, and calculating interest, then rounding to 
> the nearest cent) you have to care about bias.

If I'm paying off a loan, it's what the bank calculates that
matters, not what I calculate. And I hope the bank isn't
relying on the vagaries of Python floating point arithmetic
for its critical financial calculations.


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