Decimals to 2 places for money in Python 3

Question

How do I get my decimals to stay at 2 places for representing money using the decimal module?

I\'ve setting the precision, and damn near everything else

Answer 1

The accepted answer is mostly correct, except for the constant to use for the rounding operation. You should use ROUND_HALF_UP instead of ROUND_05UP for currency operations. According to the docs:

decimal.ROUND_HALF_UP

    Round to nearest with ties going away from zero.

decimal.ROUND_05UP

    Round away from zero if last digit after rounding towards zero would have been 0 or 5; otherwise round towards zero.

Using ROUND_05UP would only round up (for positive numbers) if the number in the hundredths place was a 5 or 0, which isn't correct for currency math.

Here are some examples:

>>> from decimal import Decimal, ROUND_05UP, ROUND_HALF_UP
>>> cents = Decimal('0.01')
>>> Decimal('1.995').quantize(cents, ROUND_HALF_UP)
Decimal('2.00')  # Correct
>>> Decimal('1.995').quantize(cents, ROUND_05UP)
Decimal('1.99')  # Incorrect
>>> Decimal('1.001').quantize(cents, ROUND_HALF_UP)
Decimal('1.00')  # Correct
>>> Decimal('1.001').quantize(cents, ROUND_05UP)
Decimal('1.01')  # Incorrect