updates

20210806111448-working_with_currencies.org

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+:PROPERTIES:
+:ID:       36fa073d-4b34-4b2b-bf96-0994a44df61e
+:END:
+#+title: Working with currencies
+
+- https://simple.wikipedia.org/wiki/ISO_4217
+
+#+begin_src python :exports both
+  from decimal import Decimal
+
+  import pint
+  from iso_4217 import define_currency_units
+
+  currency_units = define_currency_units(pint.UnitRegistry(non_int_type=Decimal))
+
+
+  def to_base_units(currency: str, amount: int) -> Decimal:
+      """Convert an amount in a currency's smallest denomination to its base.
+
+      e.g. a USD value in its lowest denomination (cents) as 1999 would convert to
+      19.99 (dollars).
+      """
+      subunit = currency_units[f'{currency.upper()}s']
+      return (subunit * amount).to_base_units().magnitude
+
+
+  return to_base_units('USD', 1999)
+#+end_src
+
+#+RESULTS: