money-lib 1.1.0

Python 3 money lib with decimal precision and currency exchange support.

money-lib

Python 3 money lib with decimal precision and currency exchange support.

Installation

Install the latest release with:

pip install money-lib

Usage

A Currency object can be created with a currency_code (must be a string and valid ISO 4217 format: ^[A-Z]{3}$).

>>> from money.currency import Currency
>>> currency = Currency('USD')
>>> currency
USD

A Money object can be created with an amount (can be any valid value in decimal.Decimal(value)) and a currency (can be a string or a Currency(code) object).

>>> from money.money import Money
>>> money = Money('7.37', 'USD')
>>> money
USD 7.37

Money objects are immutable by convention and hashable. Once created, you can use read-only properties real (decimal.Decimal), amount (decimal.Decimal) and currency (Currency) to access its internal components. The real property returns the stored amount used for calculations and amount returns the amount rounded to the correct number of decimal places for the currency.

>>> money = Money('6.831', 'USD')
>>> money.real
Decimal('6.831')
>>> money.amount
Decimal('6.83')
>>> money.currency
USD

Money emulates a numeric type and you can apply most arithmetic and comparison operators between money objects, integers (int) and decimal numbers (decimal.Decimal).

>>> money = Money('5', 'USD')
>>> money / 2
USD 2.50
>>> money + Money('10', 'USD')
USD 15.00

All arithmetic operators support automatic currency conversion as long as you have a currency exchange backend setup. The currency of the leftmost object has priority.

# Assuming the rate from USD to EUR is 2
>>> money = Money('7.50', 'USD')
>>> money + Money('5', 'EUR')
USD 10.00

Currency exchange

Currency exchange works by setting a backend class that implements the abstract base class money.exchange.BaseBackend. Its API is exposed through money.xrates, along with xrates.backend and xrates.backend_name.

A simple proof-of-concept backend money.exchange.SimpleBackend is included.

from decimal import Decimal
from money.money import Money, xrates

xrates.backend = 'money.exchange.SimpleBackend'
xrates.base = 'USD'
xrates.setrate('AAA', Decimal('2'))
xrates.setrate('BBB', Decimal('8'))

a = Money(1, 'AAA')
b = Money(1, 'BBB')

assert a.to('BBB') == Money('4', 'BBB')
assert b.to('AAA') == Money('0.25', 'AAA')
assert a + b == Money('1.25', 'AAA')

Credits

Most of the code is based of https://github.com/carlospalol/money.

Currency data and formatting is powered by Babel.