class altair.LookupTransform(lookup=Undefined, default=Undefined, **kwds)

LookupTransform schema wrapper

Mapping(required=[lookup, from])


Key in primary data source.


The default value to use if lookup fails.

Default value: null

asanyOf(FieldName, List(FieldName))

The output fields on which to store the looked up data values.

For data lookups, this property may be left blank if from.fields has been specified (those field names will be used); if from.fields has not been specified, as must be a string.

For selection lookups, this property is optional: if unspecified, looked up values will be stored under a property named for the selection; and if specified, it must correspond to from.fields.

fromanyOf(LookupData, LookupSelection)

Data source or selection for secondary data reference.

__init__(lookup=Undefined, default=Undefined, **kwds)


__init__([lookup, default])

copy([deep, ignore])

Return a copy of the object

from_dict(dct[, validate, _wrapper_classes])

Construct class from a dictionary representation

from_json(json_string[, validate])

Instantiate the object from a valid JSON string


Resolve references in the context of this object's schema or root schema.

to_dict([validate, ignore, context])

Return a dictionary representation of the object

to_json([validate, ignore, context, indent, ...])

Emit the JSON representation for this object as a string.

validate(instance[, schema])

Validate the instance against the class schema in the context of the rootschema.

validate_property(name, value[, schema])

Validate a property against property schema in the context of the rootschema