Looks like both 4.5 and 5.5 have exact float representations in Python 3.5:
>>> from decimal import Decimal
>>> Decimal(4.5)
Decimal('4.5')
>>> Decimal(5.5)
Decimal('5.5')
If this is the case, then why
>>> round(4.5)
4
>>> round(5.5)
6
?
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Aivar
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2Banker's rounding. You round to the nearest even number – 3Doubloons Oct 04 '16 at 14:46
2 Answers
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In Python 3, exact half way numbers are rounded to the nearest even result. This behavior changed in Python 3
The
round()function rounding strategy and return type have changed. Exact halfway cases are now rounded to the nearest even result instead of away from zero. (For example, round(2.5) now returns 2 rather than 3.) round(x[, n]) now delegates to x.round([n]) instead of always returning a float. It generally returns an integer when called with a single argument and a value of the same type as x when called with two arguments.
Andy
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I think this can be solved using str with the round function, str(round(value)) – champion-runner Aug 25 '19 at 19:42
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Python 3 uses Bankers Rounding, which rounds .5 values to the closest even number.
Patrick Haugh
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