how to calculate float number using precision in python [duplicate]

Question

precision = 2
number = 31684.28
result = Decimal(number) - Decimal(10 ** -precision)
print(result)

Desired output:

31684.27

Actual output:

31684.26999999999883584657356

What I try to do is to subtract 0.01 from number.

Answer 1

You have to make the values with Decimal(...) not the output. So try this:

from decimal import Decimal
precision = 2
number = 31684.28
result = number - float(10 ** Decimal(-precision))
print(result)

Output:

31684.27