def transform_chart(
chart: alt.Chart, extract_encoding_transforms: bool = True
) -> alt.Chart:
"""Return a chart with the transformed data
Parameters
----------
chart : alt.Chart
The chart instance from which the data and transform
will be extracted.
extract_encoding_transforms : bool
If True (default), then also extract transforms from encodings.
Returns
-------
chart_out : alt.Chart
A copy of the input chart with the transformed data.
Example
-------
>>> import pandas as pd
>>> data = pd.DataFrame({'x': range(5), 'y': list('ABCAB')})
>>> chart = alt.Chart(data).mark_bar().encode(x='sum(x)', y='y')
>>> new_chart = transform_chart(chart)
>>> new_chart.data
y sum_x
0 A 3
1 B 5
2 C 2
>>> new_chart.encoding
FacetedEncoding({
x: PositionFieldDef({
field: FieldName('sum_x'),
title: 'Sum of x',
type: StandardType('quantitative')
}),
y: PositionFieldDef({
field: FieldName('y'),
type: StandardType('nominal')
})
})
"""
if extract_encoding_transforms:
chart = extract_transform(chart)
chart = chart.properties(data=extract_data(chart, apply_encoding_transforms=False))
chart.transform = alt.Undefined
return chart
def transform_chart(chart: alt.Chart) -> alt.Chart:
"""Return a chart with the transformed data
Parameters
----------
chart : alt.Chart
The chart instance from which the data and transform
will be extracted.
Returns
-------
chart_out : alt.Chart
A copy of the input chart with the transformed data.
"""
chart = chart.properties(data=extract_data(chart))
chart.transform = alt.Undefined
return chart
