Unit aliases

PyAnsys Units supports unit aliases so you can use shorthand or alternative names for units. For example, deg for degree or meter for m.

This example shows you how to:

• Use built-in aliases in unit and quantity creation.

• Use aliases inside compound unit strings.

• Register custom aliases programmatically.

• Perform conversions with aliased units.

Perform required imports

from ansys.units import Quantity, Unit, UnitRegistry

Built-in aliases

Several common aliases are shipped out of the box. Use deg instead of degree, rad instead of radian, meter instead of m, and so on.

angle = Unit("deg")
print(f"Unit('deg')  ->  name={angle.name!r}, sf={angle.si_scaling_factor}")

length = Unit("meter")
print(f"Unit('meter') ->  name={length.name!r}")

force = Unit("newton")
print(f"Unit('newton') ->  name={force.name!r}")

Unit('deg')  ->  name='degree', sf=0.017453292519943295
Unit('meter') ->  name='m'
Unit('newton') ->  name='N'

Aliases in quantities

Aliases work seamlessly when creating Quantity objects.

q_angle = Quantity(90, "deg")
print(f"Quantity(90, 'deg')  = {q_angle}")

q_len = Quantity(5.0, "meter")
print(f"Quantity(5.0, 'meter') = {q_len}")

Quantity(90, 'deg')  = 90.0 degree
Quantity(5.0, 'meter') = 5.0 m

Aliases in compound units

Aliases can be mixed with canonical names inside compound unit strings.

angular_velocity = Unit("deg sec^-1")
print(f"Unit('deg sec^-1') ->  name={angular_velocity.name!r}")

acceleration = Unit("meter sec^-2")
print(f"Unit('meter sec^-2') -> name={acceleration.name!r}")

Unit('deg sec^-1') ->  name='degree s^-1'
Unit('meter sec^-2') -> name='m s^-2'

Conversions with aliases

Unit conversions work normally when aliases are used.

q_deg = Quantity(180, "deg")
q_rad = q_deg.to("radian")
print(f"180 deg = {q_rad.value:.6f} radian")

q_m = Quantity(1, "meter")
q_ft = q_m.to("ft")
print(f"1 meter = {q_ft.value:.6f} ft")

180 deg = 3.141593 radian
1 meter = 3.280840 ft

Register a custom alias

You can register your own aliases at runtime via UnitRegistry.

ureg = UnitRegistry()
ureg.register_alias("angular_deg", "degree")

custom = Unit("angular_deg")
print(f"Unit('angular_deg') -> name={custom.name!r}")

Unit('angular_deg') -> name='degree'

Alias equality

A unit created from an alias is fully equal to the canonical unit.

assert Unit("deg") == Unit("degree")
assert Unit("rad") == Unit("radian")
assert Unit("meter") == Unit("m")
print("All alias-based units equal their canonical counterparts.")

All alias-based units equal their canonical counterparts.