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Why does this happen in Python:
>>>
>>> 483.6 * 3
1450.8000000000002
>>>
I know this happens in other languages, and I’m not asking how to fix this. I know you can do:
>>>
>>> from decimal import Decimal
>>> Decimal('483.6') * 3
Decimal('1450.8')
>>>
So what exactly causes this to happen? Why do decimals get slightly inaccurate when doing math like this?
Is there any specific reason the computer doesn’t get this right?
See the Python documentation on floating point numbers. Essentially when you create a floating point number you are using base 2 arithmetic. Just as 1/3 is .333…. on into infinity, so most floating point numbers cannot be exactly expressed in base 2. Hence your result.
The difference between the Python interpreter and some other languages is that others may not display these extra digits. It’s not a bug in Python, just how the hardware computes using floating-point arithmetic.