def_unit¶
-
astropy.units.
def_unit
(s, represents=None, doc=None, format=None, prefixes=False, exclude_prefixes=[], namespace=None)[source]¶ Factory function for defining new units.
- Parameters
- sstr or list of str
The name of the unit. If a list, the first element is the canonical (short) name, and the rest of the elements are aliases.
- representsUnitBase instance, optional
The unit that this named unit represents. If not provided, a new
IrreducibleUnit
is created.- docstr, optional
A docstring describing the unit.
- formatdict, optional
A mapping to format-specific representations of this unit. For example, for the
Ohm
unit, it might be nice to have it displayed as\Omega
by thelatex
formatter. In that case,format
argument should be set to:{'latex': r'\Omega'}
- prefixesbool or list, optional
When
True
, generate all of the SI prefixed versions of the unit as well. For example, for a given unitm
, will generatemm
,cm
,km
, etc. When a list, it is a list of prefix definitions of the form:(short_names, long_tables, factor)
Default is
False
. This function always returns the base unit object, even if multiple scaled versions of the unit were created.- exclude_prefixeslist of str, optional
If any of the SI prefixes need to be excluded, they may be listed here. For example,
Pa
can be interpreted either as “petaannum” or “Pascal”. Therefore, when defining the prefixes fora
,exclude_prefixes
should be set to["P"]
.- namespacedict, optional
When provided, inject the unit (and all of its aliases and prefixes), into the given namespace dictionary.
- Returns
- unit
UnitBase
object The newly-defined unit, or a matching unit that was already defined.
- unit