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.

Conversions ‘on the fly’

The convert method is quick way to do conversions on the fly:

from pyrcurrency.converter import convert
convert(125,'EUR','GBP')
109.504265

>>> from pycurrency.converter import convert
>>> result = convert(125,'EUR','GBP')
>>> type(result)
<type 'float'>