QuantityAttribute

class astropy.coordinates.QuantityAttribute(default, secondary_attribute='', unit=None, shape=None)[source]

Bases: astropy.coordinates.Attribute

A frame attribute that is a quantity with specified units and shape (optionally).

Parameters
defaultobject

Default value for the attribute if not provided

secondary_attributestr

Name of a secondary instance attribute which supplies the value if default is None and no value was supplied during initialization.

unitunit object or None

Name of a unit that the input will be converted into. If None, no unit-checking or conversion is performed

shapetuple or None

If given, specifies the shape the attribute must be

Methods Summary

convert_input(self, value)

Checks that the input is a Quantity with the necessary units (or the special value 0).

Methods Documentation

convert_input(self, value)[source]

Checks that the input is a Quantity with the necessary units (or the special value 0).

Parameters
valueobject

Input value to be converted.

Returns
out, convertedcorrectly-typed object, boolean

Tuple consisting of the correctly-typed object and a boolean which indicates if conversion was actually performed.

Raises
ValueError

If the input is not valid for this attribute.