altair.SecondaryFieldDef

class altair.SecondaryFieldDef(aggregate=Undefined, band=Undefined, bin=Undefined, field=Undefined, timeUnit=Undefined, title=Undefined, **kwds)

SecondaryFieldDef schema wrapper

Mapping(required=[]) A field definition of a secondary channel that shares a scale with another primary channel. For example, x2, xError and xError2 share the same scale with x.

Attributes

aggregateAggregate

Aggregation function for the field (e.g., "mean", "sum", "median", "min", "max", "count" ).

Default value: undefined (None)

See also: aggregate documentation.

bandfloat

For rect-based marks ( rect, bar, and image ), mark size relative to bandwidth of band scales, bins or time units. If set to 1, the mark size is set to the bandwidth, the bin interval, or the time unit interval. If set to 0.5, the mark size is half of the bandwidth or the time unit interval.

For other marks, relative position on a band of a stacked, binned, time unit or band scale. If set to 0, the marks will be positioned at the beginning of the band. If set to 0.5, the marks will be positioned in the middle of the band.

binNone

A flag for binning a quantitative field, an object defining binning parameters, or indicating that the data for x or y channel are binned before they are imported into Vega-Lite ( "binned" ).

If true, default binning parameters will be applied.

If "binned", this indicates that the data for the x (or y ) channel are already binned. You can map the bin-start field to x (or y ) and the bin-end field to x2 (or y2 ). The scale and axis will be formatted similar to binning in Vega-Lite. To adjust the axis ticks based on the bin step, you can also set the axis’s tickMinStep property.

Default value: false

See also: bin documentation.

fieldField

Required. A string defining the name of the field from which to pull a data value or an object defining iterated values from the repeat operator.

See also: field documentation.

Notes: 1) Dots ( . ) and brackets ( [ and ] ) can be used to access nested objects (e.g., "field": "foo.bar" and "field": "foo['bar']" ). If field names contain dots or brackets but are not nested, you can use \ to escape dots and brackets (e.g., "a\.b" and "a\[0\]" ). See more details about escaping in the field documentation. 2) field is not required if aggregate is count.

timeUnitanyOf(TimeUnit, TimeUnitParams)

Time unit (e.g., year, yearmonth, month, hours ) for a temporal field. or a temporal field that gets casted as ordinal.

Default value: undefined (None)

See also: timeUnit documentation.

titleanyOf(Text, None)

A title for the field. If null, the title will be removed.

Default value: derived from the field’s name and transformation function ( aggregate, bin and timeUnit ). If the field has an aggregate function, the function is displayed as part of the title (e.g., "Sum of Profit" ). If the field is binned or has a time unit applied, the applied function is shown in parentheses (e.g., "Profit (binned)", "Transaction Date (year-month)" ). Otherwise, the title is simply the field name.

Notes :

1) You can customize the default field title format by providing the fieldTitle property in the config or fieldTitle function via the compile function’s options.

2) If both field definition’s title and axis, header, or legend title are defined, axis/header/legend title will be used.

__init__(aggregate=Undefined, band=Undefined, bin=Undefined, field=Undefined, timeUnit=Undefined, title=Undefined, **kwds)

Methods

__init__([aggregate, band, bin, field, ...])
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([schema])	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