Pint

This code make all kind of units available as UNITS.unit:

import pint
UNITS = pint.UnitRegistry()
Quantity = UNITS.Quantity

To see all units available open the python shell:

>>> UNITS. and press <tab> twice. To limit the list type the first character(s) of the unit >>> UNITS.a

You can specify formulas with units.

The formula for gravity acceleration:

meter = UNITS.meter
second = UNITS.second
acc = 9.8 * meter / second ** 2

time = 9 * second
speed = acc * time
print(speed)

Output: 88.2 meter / second

unitaval.to(UNITS.unitb)

Convert the unita to unitb

Conversion of compatible units is on the fly. The first unit in the calculation defines the output unit.

Example:

distance = 15 * meter
distance.to(UNITS.yard)

Output: <Quantity(16.404199475065617, 'yard')>