Datum#

class lsst.verify.Datum(quantity=None, unit=None, label=None, description=None)#

Bases: QuantityAttributeMixin, JsonSerializationMixin

A value annotated with units, a plot label and description.

Datum supports natively support Astropy Quantity and units. In addition, a Datum can also wrap strings, booleans and integers. A Datums’s value can also be None.

Parameters#

quantityastropy.units.Quantity, int, float or iterable.: Value of the Datum.
unitstr: Units of quantity as a str if quantity is not supplied as an astropy.units.Quantity. See http://docs.astropy.org/en/stable/units/. Units are not used by str, bool, int or None types.
labelstr, optional: Label suitable for plot axes (without units).
descriptionstr, optional: Extended description of the Datum.

Attributes Summary

`description`	Extended description.
`json`	Datum as a `dict` compatible with overall `Job` JSON schema.
`label`	Label for plotting (without units).

Methods Summary

deserialize([label, description, value, unit])

Deserialize fields from a Datum JSON object into a Datum instance.

Attributes Documentation

description#: Extended description.

json#: Datum as a dict compatible with overall Job JSON schema.

label#: Label for plotting (without units).

Methods Documentation

classmethod deserialize(label=None, description=None, value=None, unit=None)#

Deserialize fields from a Datum JSON object into a Datum instance.

Parameters#

valuefloat, int, bool, str, or list: Values, which may be scalars or lists of scalars.
unitstr or None: An astropy.units-compatible string with units of value, or None if the value does not have physical units.
labelstr, optional: Label suitable for plot axes (without units).
descriptionstr, optional: Extended description of the Datum.

Returns#

datumDatum: Datum instantiated from provided JSON fields.

Examples#

With this class method, a Datum may be round-tripped from its JSON serialized form.

>>> datum = Datum(50. * u.mmag, label='sigma',
...               description="Photometric uncertainty.")
>>> print(datum)
sigma = 50.0 mmag
Photometric uncertainty.
>>> json_data = datum.json
>>> new_datum = datum.deserialize(**json_data)
>>> print(new_datum)
sigma = 50.0 mmag
Photometric uncertainty.