UnitManager

class bookkeep.UnitManager(clients, *args, **kwargs)

Create a UnitManager object for handling units of measure of a list of dictionaries (clients). When an item in UnitManger changes, all dictionaries in clients with the same key change values accordingly.

Parameters

clients: [list] All dictionaries managed by UnitManager object.

*args: Key/units pairs.

**kwargs: Key/units pairs.

Class Attribute

Quantity: pint Quantity class for compatibility.

Examples

Convert units of all clients using a UnitManager.

Create client dictionaries:

>>> car = {'weight': 4000, 'velocity': 50}
>>> plane = {'weight': 175000, 'velocity': 600}

Create a UnitManager object:

>>> um = UnitManager([car, plane], weight='lbs', velocity='mph')
>>> um
UnitManager:
{'weight': 'lbs',
 'velocity': 'mph'}

Change units of clients:

>>> um['weight'] = 'kg'
>>> um['velocity'] = 'km/hr'
>>> car
{'weight': 1814.36948, 'velocity': 80.46719999999999}
>>> plane
{'weight': 79378.66475000001, 'velocity': 965.6063999999999}

Quantity objects are also compatible with UnitManager objects, so long as they are set as the “Quantity” class attribute.

Set “Quantity” attribute:

>>> from pint import UnitRegistry
>>> ureg = UnitRegistry()
>>> UnitManager.Quantity = Q_ = ureg.Quantity

Set a Quantity object and change units:

>>> car['weight'] = Q_(4000, 'lb')
>>> um['weight'] = 'kg'
>>> car
{'weight': <Quantity(1814.36948, 'kilogram')>,
 'velocity': 80.46719999999999>}

class Quantity