Units

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Units#

Units are measures of dimensions: metres for length, seconds for time, joules for energy. unxt.units provides two functions, both re-exported on the top-level unxt namespace.

Function

Purpose

unxt.unit

Construct a unit.

unxt.unit_of

Return the unit of an object, or None if it has none.

Both are multiple-dispatch functions; the registered signatures are listed in the API reference.

>>> import unxt as u

>>> u.unit
<multiple-dispatch function unit (...)>

>>> u.unit_of
<multiple-dispatch function unit_of (...)>

unit#

Accepts a string or an existing unit object; the unit backend is astropy.units, so the returned object is an astropy Unit.

>>> m = u.unit('m')  # from a str
>>> m
Unit("m")

>>> u.unit(m)  # from a unit object
Unit("m")

Units compose arithmetically:

>>> u.unit("km") / u.unit("h")
Unit("km / h")

unit_of#

Returns the unit of an object. Objects that carry no unit — strings, for example — return None.

>>> print(u.unit_of("m"))  # strings have no units
None

>>> u.unit_of(m)  # from a unit object
Unit("m")

>>> q = u.Q(5, 'm')  # from a Quantity
>>> u.unit_of(q)
Unit("m")

See also#

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