Python 3 Object-Oriented Programming - Third Edition

Making it look right

It's nice to be able to include variables in template strings, but sometimes the variables need a bit of coercion to make them look the way we want them to in the output. For example, if we are performing calculations with currency, we may end up with a long decimal that we don't want to show up in our template:

subtotal = 12.32tax = subtotal * 0.07total = subtotal + taxprint(    "Sub: ${0} Tax: ${1} Total: ${total}".format(        subtotal, tax, total=total    ))

If we run this formatting code, the output doesn't quite look like proper currency:

Sub: $12.32 Tax: $0.8624 Total: $13.182400000000001

Technically, we should never use floating-point numbers in currency calculations like this; we should construct decimal.Decimal() objects ...