Overview

This package is designed to easily work with physical units. The main usage is to display different units and unit systems in FrontEnds. Typical use case would be: Your application make it’s calculation in SI units and then you’ll need to deploy your application in the US. So instead of display temperatures in °C you’ll now have to display it in °F.

Warning: It should never be used to make precise calculations, since the accuracy is limited to 3-4 digits at the moment. Especially when converting SI units to imperial units.

Converting your first value

The following example illustrates how to convert from one unit to another in the same type of physical unit (e.g. lengths):

from pyUnitTypes.length import Meter, KiloMeter, MilliMeter, Inch

# define the value as KiloMeter
a_long_distance = KiloMeter(2.5)
a_short_distance = Inch(1)

# print the value as Meter
print(Meter(a_long_distance))
print(MilliMeter(a_short_distance))

The output will look like this:

Calculating with units

Calculation with unit values is as easy as normal calculation. Sofar following operators are implemented:

Arithmetic Operators

The following mathematical operators can be used to calculate with the units.

  • add (+): Works as within a UnitType package. Raises a TypeError if Units from different modules are used.

    from pyUnitTypes.length import Meter, KiloMeter

two_kilometer = Meter(1000) + KiloMeter(1)

  • sub (-): Works as within a UnitType package. Raises a TypeError if Units from different modules are used.

    from pyUnitTypes.length import Meter, KiloMeter

half_kilometer = KiloMeter(1) - Meter(500)

  • mul (*): Works when multiplied with float or int.

    Raises pyUnitTypes.basics.UnknownUnitMultiplicationError when multiplication of the two units has not been implemented

    Raises TypeError if multiplied with objects which are not inherited from pUnitTypes.basics.BaseUnit.

    from pyUnitTypes.length import Meter, KiloMeter

five_kilometer = KiloMeter(2) * 2.5

  • div (*): Works when divided by float or int.

    Raises pyUnitTypes.basics.UnknownUnitDivisionError when division of the two units has not been implemented or if division of float or int by the unit is not implemented.

    Raises TypeError if multiplied with objects which are not inherited from pUnitTypes.basics.BaseUnit.

    from pyUnitTypes.length import Meter, KiloMeter

four_kilometer = KiloMeter(10) / 2.5

Comparison Operators

Any pyUnitTypes object can be compared to another object from the same module. Comparing to a object of a different package or any other object will raise as TypeError.

from pyUnitTypes.length import Meter, KiloMeter

is_eq = Meter(1000) == KiloMeter(1)
is_ne = Meter(0) != KiloMeter(1)
is_lt = Meter(1) < KiloMeter(1)
is_gt = Meter(2000) > KiloMeter(1)
is_le = Meter(1000) >= KiloMeter(1)
is_ge = Meter(1000) <= KiloMeter(1)

Other numeric functionality

Besides the four basic arithmetic operators several other mathematical operations are supported:

  • round()
  • math.ceil()
  • math.floor()
  • __neg__: Meter(-1) is equal to -Meter(1)
  • __pos__: Meter(+1) is equal to +Meter(1)

All pyUnitType objects can be converted to int or float.