Welcome to the linearmoney library's documentation!

linearmoney is a library for working with multiple currencies that uses a non-traditional model based on linear algebra to allow lossless currency conversion and calculations with multiple currencies simultaneously.

Understanding of linear algebra is not required to use the linearmoney library, and the library is designed in such a way that the same code can be used for single and multi-currency calculations, so the programmer no longer has to worry about keeping track of individual currencies, and in most cases, doesn't even need to know which currency a particular value is in. This makes developing modern international applications much simpler.

Currencies can be easily converted based on exchange rates, and full localization support is built-in.

The linearmoney library uses a completely thread-safe functional/procedural style that is verbose but very clear in its behavior with no mutable data or side effects.

This makes it ideal for other library/framework authors to use for core currency functionalities while providing a higher level API for use by end-users, but application developers can still use the library directly if they prefer as all of the core functionalities of a monetary application are provided (conversion, localization/formatting, rates/data management).

Basic Usage

pip install linearmoney

>>> import linearmoney as lm
>>> fo = lm.vector.forex({"base": "usd", "rates": {"jpy": 100}})  # 1 USD -> 100 JPY
>>> sp = lm.vector.space(fo)
>>> cart = []
>>> local_milk_price = lm.vector.asset(4.32, "usd", sp)
>>> cart.append(local_milk_price)
>>> foreign_eggs_price = lm.vector.asset(545, "jpy", sp)
>>> cart.append(foreign_eggs_price)
>>> sales_tax = 0.095
>>> subtotal = sum(cart)
>>> total = subtotal + (subtotal * sales_tax)
>>> total_usd = lm.vector.evaluate(total, "usd", fo)
>>> total_jpy = lm.vector.evaluate(total, "jpy", fo)
>>> usd = lm.data.currency("usd")
>>> jpy = lm.data.currency("jpy")
>>> rounded_total_usd = lm.scalar.roundas(total_usd, usd)
>>> rounded_total_jpy = lm.scalar.roundas(total_jpy, jpy)
>>> en_US = lm.data.locale("en", "us")
>>> localized_total_usd = lm.scalar.l10n(rounded_total_usd, usd, en_US)
>>> localized_total_jpy = lm.scalar.l10n(rounded_total_jpy, jpy, en_US)
>>> print(localized_total_usd)
$10.70
>>> print(localized_total_jpy)
¥1,070