Truncating decimal digits like Excel in python

Question

In my excel file, I've some calculations. Calculation returns 0,345 and excel convert it to 0,35. I made it in python. Python is returning 0,345, but I want to take 0,35 like Excel. I've tried with round() method, but it's returning 0.34.

calc = round(value * arg / 1000, 5)

Answer 1

Floating point numbers are inherently imprecise. Where n is the number of digits to round to, multiply by 10ⁿ, add 0.5, round, then divide by 10ⁿ.

>>> number = 0.345
>>> round(number * 10 ** 2 + 0.5) / 10 ** 2
0.35