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Note

This is an old version of the documentation. See http://docs.astropy.org/en/stable for the latest version.

QuantityFrameAttribute

class astropy.coordinates.QuantityFrameAttribute(default=None, secondary_attribute=u'', unit=None, shape=None)[source] [edit on github]

Bases: astropy.coordinates.FrameAttribute

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

Parameters:

default : object

Default value for the attribute if not provided

secondary_attribute : str

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

unit : unit object or None

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

shape : tuple or None

If given, specifies the shape the attribute must be

Methods Summary

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

Methods Documentation

convert_input(value)[source] [edit on github]

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

Parameters:

value : object

Input value to be converted.

Returns:

out, converted : correctly-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.

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