This website is for version 5. You can find the documentation for version 4 here.


class altair.VariableParameter(name=Undefined, bind=Undefined, expr=Undefined, value=Undefined, **kwds)#

VariableParameter schema wrapper

namestr, ParameterName

A unique name for the variable parameter. Parameter names should be valid JavaScript identifiers: they should contain only alphanumeric characters (or “$”, or “_”) and may not start with a digit. Reserved keywords that may not be used as parameter names are “datum”, “event”, “item”, and “parent”.

binddict, Binding, BindInput, BindRange, BindDirect, BindCheckbox, BindRadioSelect

Binds the parameter to an external input element such as a slider, selection list or radio button group.

exprstr, Expr

An expression for the value of the parameter. This expression may include other parameters, in which case the parameter will automatically update in response to upstream parameter changes.


The initial value of the parameter.

Default value: undefined

__init__(name=Undefined, bind=Undefined, expr=Undefined, value=Undefined, **kwds)#


__init__([name, bind, expr, value])

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, indent, sort_keys, ...])

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