Floor division with small numbers returning wrong answer [duplicate]

Question

I'm trying to do some calculations in my python script but i'm getting some weird results. For example:

0.03 // 0.01
>>> 2.0

If I upscale the numbers I get the expected results:

3.0 // 1.0
>>> 3.0

I'm pretty sure that the answer for the first code snippet should be 3.0 and not 2.0. Can someone explain me why this is happening and how to fix it?

Answer 1

This is due to the floating point error. Note that with the above floor division, the remainder is not 0:

0.03 % 0.01
# 0.009999999999999998

So if instead we divide by:

0.03 // 0.009
# 3.0

The answer is correct. Hence 0.03 is not entirely divisible by 0.01 without some remainder due to floating point limitations

Answer 2

As yatu already mentioned, this is due to floating point errors. Try this instead:

from decimal import Decimal
Decimal('0.03') // Decimal('0.01')
>>> 3