Low-level unit conversion¶
Conversion of quantities from one unit to another is handled using the
Quantity.to method. This page
describes some low-level features for handling unit conversion that
are rarely required in user code.
There are two ways of handling conversions between units.
In this case, given a source and destination unit, the value(s) in the new units is(are) returned.
>>> from astropy import units as u >>> u.pc.to(u.m, 3.26) 1.0059308915583043e+17
This converts 3.26 parsecs to meters.
Arrays are permitted as arguments.
>>> u.h.to(u.s, [1, 2, 5, 10.1]) array([ 3600., 7200., 18000., 36360.])
If you attempt to convert to a incompatible unit, an exception will result:
>>> cms = u.cm / u.s >>> cms.to(u.km) Traceback (most recent call last): ... UnitConversionError: 'cm / s' (speed) and 'km' (length) are not convertible
You can check whether a particular conversion is possible using the
>>> u.m.is_equivalent(u.pc) True >>> u.m.is_equivalent("second") False >>> (u.m ** 3).is_equivalent(u.l) True