pycurrency examples

This serves as primitive test suite and documentation of some examples.

Using the Converter

First import converter from the pycurrency module:

>>> from pycurrency import converter
>>> myconverter = converter.Converter(1,'USD','JMD')

Now let’s test it:

>>> result = myconverter.result()
>>> result = float(result)
>>> type(result)
<type 'float'>

It should be possible to also change currency:

>>> myconverter.from_cur = 'EUR'
>>> myconverter.query['from']
'USD'
>>> output = myconverter.update()
>>> myconverter.query['from']
'EUR'

The rates dictionary (repsonsible usage)

PyCurrency supports the concept of a rates dictionary a rate is stored as a float and represented in the form [from_cur]-[to_cur] e.g. USD-JMD means the cost of 1 USD in JMD. see the example below:

>>> rates = {'EUR-USD':3.1}

The Converter accepts an optional ‘rates’ dictonary as an argument on instantiation:

>>> myconverter = converter.Converter(1,'USD','JMD',rates)

The add_rate() method can be used to load new rates at anytime:

>>> myconverter.add_rate('USD-JMD',85.6)

Rates are stored in a rates dictionary (_rates).

>>> int(myconverter._rates['USD-JMD'])
85
>>> int(myconverter._rates['EUR-USD'])
3

There is also a rates method which, by default, retrieves all rates:

>>> allrates = myconverter.rates()
>>> int(allrates['USD-JMD'])
85
>>> int(allrates['EUR-USD'])
3

The default behaviour of the Converter object is to check the rates first before polling Google for rates. If there is no existing rate it will search for a inverse rate, for example a JMD-USD conversion could be treated as an inverse rate of USD-JMD (using the formula Amount * 1/rate). If there is neither a matching inverse rate or rate then it ‘polls’ Google for the current rate and adds it to rate dictionary.