altair.FacetSpec

class altair.FacetSpec(facet=Undefined, spec=Undefined, align=Undefined, bounds=Undefined, center=Undefined, columns=Undefined, data=Undefined, description=Undefined, name=Undefined, resolve=Undefined, spacing=Undefined, title=Undefined, transform=Undefined, **kwds)

FacetSpec schema wrapper

Mapping(required=[facet, spec]) Base interface for a facet specification.

Attributes

facetanyOf(FacetFieldDefFieldName, FacetMappingFieldName)

Definition for how to facet the data. One of: 1) a field definition for faceting the plot by one field 2) An object that maps row and column channels to their field definitions

specanyOf(LayerSpec, FacetedUnitSpec)

A specification of the view that gets faceted.

alignanyOf(LayoutAlign, RowColLayoutAlign)

The alignment to apply to grid rows and columns. The supported string values are "all", "each", and "none".

• For "none", a flow layout will be used, in which adjacent subviews are simply placed one after the other.

• For "each", subviews will be aligned into a clean grid structure, but each row or column may be of variable size.

• For "all", subviews will be aligned and each row or column will be sized identically based on the maximum observed size. String values for this property will be applied to both grid rows and columns.

Alternatively, an object value of the form {"row": string, "column": string} can be used to supply different alignments for rows and columns.

Default value: "all".

boundsenum(‘full’, ‘flush’)

The bounds calculation method to use for determining the extent of a sub-plot. One of full (the default) or flush.

• If set to full, the entire calculated bounds (including axes, title, and legend) will be used.

• If set to flush, only the specified width and height values for the sub-view will be used. The flush setting can be useful when attempting to place sub-plots without axes or legends into a uniform grid structure.

Default value: "full"

centeranyOf(boolean, RowColboolean)

Boolean flag indicating if subviews should be centered relative to their respective rows or columns.

An object value of the form {"row": boolean, "column": boolean} can be used to supply different centering values for rows and columns.

Default value: false

columnsfloat

The number of columns to include in the view composition layout.

Default value : undefined – An infinite number of columns (a single row) will be assumed. This is equivalent to hconcat (for concat ) and to using the column channel (for facet and repeat ).

Note :

1. This property is only for:

• the general (wrappable) concat operator (not hconcat / vconcat )

• the facet and repeat operator with one field/repetition definition (without row/column nesting)

2) Setting the columns to 1 is equivalent to vconcat (for concat ) and to using the row channel (for facet and repeat ).

dataanyOf(Data, None)

An object describing the data source. Set to null to ignore the parent’s data source. If no data is set, it is derived from the parent.

descriptionstring

Description of this mark for commenting purpose.

namestring

Name of the visualization for later reference.

resolveResolve

Scale, axis, and legend resolutions for view composition specifications.

spacinganyOf(float, RowColnumber)

The spacing in pixels between sub-views of the composition operator. An object of the form {"row": number, "column": number} can be used to set different spacing values for rows and columns.

Default value : Depends on "spacing" property of the view composition configuration ( 20 by default)

titleanyOf(Text, TitleParams)

Title for the plot.

transformList(Transform)

An array of data transformations such as filter and new field calculation.

__init__(self, facet=Undefined, spec=Undefined, align=Undefined, bounds=Undefined, center=Undefined, columns=Undefined, data=Undefined, description=Undefined, name=Undefined, resolve=Undefined, spacing=Undefined, title=Undefined, transform=Undefined, **kwds)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(self[, facet, spec, align, bounds, …])	Initialize self.
copy(self[, 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([schema])	Resolve references in the context of this object’s schema or root schema.
to_dict(self[, validate, ignore, context])	Return a dictionary representation of the object
to_json(self[, validate, ignore, context, …])	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

copy(self, deep=True, ignore=())

Return a copy of the object

Parameters

deepboolean or list, optional

If True (default) then return a deep copy of all dict, list, and SchemaBase objects within the object structure. If False, then only copy the top object. If a list or iterable, then only copy the listed attributes.

ignorelist, optional

A list of keys for which the contents should not be copied, but only stored by reference.

classmethod from_dict(dct, validate=True, _wrapper_classes=None)

Construct class from a dictionary representation

Parameters

dctdictionary

The dict from which to construct the class

validateboolean

If True (default), then validate the input against the schema.

_wrapper_classeslist (optional)

The set of SchemaBase classes to use when constructing wrappers of the dict inputs. If not specified, the result of cls._default_wrapper_classes will be used.

Returns

objSchema object

The wrapped schema

Raises

jsonschema.ValidationError :

if validate=True and dct does not conform to the schema

classmethod from_json(json_string, validate=True, **kwargs)

Instantiate the object from a valid JSON string

Parameters

json_stringstring

The string containing a valid JSON chart specification.

validateboolean

If True (default), then validate the input against the schema.

**kwargs :

Additional keyword arguments are passed to json.loads

Returns

chartChart object

The altair Chart object built from the specification.

classmethod resolve_references(schema=None)

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

to_dict(self, validate=True, ignore=None, context=None)

Return a dictionary representation of the object

Parameters

validateboolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignorelist

A list of keys to ignore. This will not passed to child to_dict function calls.

contextdict (optional)

A context dictionary that will be passed to all child to_dict function calls

Returns

dctdictionary

The dictionary representation of this object

Raises

jsonschema.ValidationError :

if validate=True and the dict does not conform to the schema

to_json(self, validate=True, ignore=[], context={}, indent=2, sort_keys=True, **kwargs)

Emit the JSON representation for this object as a string.

Parameters

validateboolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignorelist

A list of keys to ignore. This will not passed to child to_dict function calls.

contextdict (optional)

A context dictionary that will be passed to all child to_dict function calls

indentinteger, default 2

the number of spaces of indentation to use

sort_keysboolean, default True

if True, sort keys in the output

**kwargs

Additional keyword arguments are passed to json.dumps()

Returns

specstring

The JSON specification of the chart object.

classmethod validate(instance, schema=None)

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

classmethod validate_property(name, value, schema=None)

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