Currency converter

This is a currency converter that uses historical rates against a reference currency (Euro).

Currency data sources

The default source is the European Central Bank. This is the ECB historical rates for 42 currencies against the Euro since 1999. It can be downloaded here: eurofxref-hist.zip. The converter can use different sources as long as the format is the same.

Installation

You can install directly after cloning:

$ python setup.py install --user

Or use the Python package:

$ pip install --user currencyconverter

Command line tool

After installation, you should have currency_converter in your $PATH:

$ currency_converter 100 USD --to EUR
100.000 USD = 87.512 EUR on 2016-05-06

Python API

Create once the currency converter object:

>>> from currency_converter import CurrencyConverter
>>> c = CurrencyConverter()

Convert from EUR to USD using the last available rate:

>>> c.convert(100, 'EUR', 'USD') # doctest: +SKIP
137.5...

Default target currency is EUR:

>>> c.convert(100, 'EUR')
100.0
>>> c.convert(100, 'USD') # doctest: +SKIP
72.67...

You can change the date of the rate:

>>> from datetime import date # datetime works too
>>> c.convert(100, 'EUR', 'USD', date=date(2013, 3, 21))
129...

Fallbacks

Some rates are missing:

>>> c.convert(100, 'BGN', date=date(2010, 11, 21))
Traceback (most recent call last):
RateNotFoundError: BGN has no rate for 2010-11-21

But we have a fallback mode for those, using a linear interpolation of the closest known rates, as long as you ask for a date within the currency date bounds:

>>> c = CurrencyConverter(fallback_on_missing_rate=True)
>>> c.convert(100, 'BGN', date=date(2010, 11, 21))
51.12...

We also have a fallback mode for dates outside the currency bounds:

>>> c = CurrencyConverter()
>>> c.convert(100, 'EUR', 'USD', date=date(1986, 2, 2))
Traceback (most recent call last):
RateNotFoundError: 1986-02-02 not in USD bounds 1999-01-04/2016-04-29
>>> 
>>> c = CurrencyConverter(fallback_on_wrong_date=True)
>>> c.convert(100, 'EUR', 'USD', date=date(1986, 2, 2)) # fallback to 1999-01-04
117.89...

Other attributes

bounds lets you know the first and last available date for each currency

>>> first_date, last_date = c.bounds['USD']
>>> first_date
datetime.date(1999, 1, 4)
>>> last_date # doctest: +SKIP
datetime.date(2016, 11, 14)

currencies is a set containing all available currencies

>>> c.currencies # doctest: +SKIP
set(['SGD', 'CAD', 'SEK', 'GBP', ...
>>> 'AAA' in c.currencies
False
>>> c.convert(100, 'AAA')
Traceback (most recent call last):
ValueError: AAA is not a supported currency

Finally, you can use your own currency file, as long as it has the same format (ECB):

# Load the packaged data (might not be up to date)
c = CurrencyConverter()

# Load the up to date full history
c = CurrencyConverter('http://www.ecb.int/stats/eurofxref/eurofxref-hist.zip')

# Load only the latest rates (single day data source)
c = CurrencyConverter('http://www.ecb.europa.eu/stats/eurofxref/eurofxref.zip')

# Load your custom file
c = CurrencyConverter('./path/to/currency/file.csv')

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