How to round 0.055 to 0.06 in Python?

Question

Result of a simple division -34.11/2 returns -17.055 Is there a python function that would return round up decimal? I am expecting to see -17.06

And yes I checked these answers, but neither can answer this question: Round up to Second Decimal Place in Python

How to round to nearest decimal in Python

Increment a Python floating point value by the smallest possible amount Python round to nearest 0.25

Any help would be greatly appreciated. Thanks!

This is, actually, answered by the questions you linked to. Please read the documentation on [Floating Point Arithmetic: Issues and Limitations](https://docs.python.org/3/tutorial/floatingpoint.html#tut-fp-issues). — Arya McCarthy, Mar 26 '20 at 13:29

score 4 · Accepted Answer · answered Mar 26 '20 at 13:31

4

This is a floating point limitation; get around it by using decimal.Decimal.

>>> from decimal import Decimal
>>> Decimal(-34.11/2)  # See? Not quite the value you thought.
Decimal('-17.05499999999999971578290569595992565155029296875')
>>> Decimal(-34.11) / Decimal(2)  # This doesn't quite work either, because -34.11 is already a little bit off.
Decimal('-17.05499999999999971578290570')
>>> Decimal("-34.11") / Decimal("2")
Decimal('-17.055')
>>> round(Decimal("-34.11") / Decimal("2"), 2)
Decimal('-17.06')

answered Mar 26 '20 at 13:31

Arya McCarthy

8,554
4
34
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The output from `round(Decimal("-34.11") / Decimal("2"), 2)` will be `'decimal.Decimal'` object. So for further calculation we need to convert it to float object right?. – mohammed wazeem Mar 26 '20 at 13:40
1

@mohammedwazeem Yes—something as simple as `float(result)`. But. If you care about the rounding of your real numbers, you probably shouldn't be using floats anyway. – Arya McCarthy Mar 26 '20 at 13:44
@AryaMcCarthy yes, nice solution. – mohammed wazeem Mar 26 '20 at 13:45

How to round 0.055 to 0.06 in Python?

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