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vega / altair

Declarative statistical visualization library for Python
https://altair-viz.github.io/
BSD 3-Clause "New" or "Revised" License
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ALTAIR EXPORT SELECTION INTO A NEW DATAFRAME OR REASSIGN VALUES TO SELECTED VALUES #3639

Closed FCalderon3006 closed 1 month ago

FCalderon3006 commented 1 month ago

What is your suggestion?

Hi Guys,

I have tried to assign a new value in a new column with the selected points in altair.chart but I was struggle on this. Anyone who can help me please? The idea is just select in the graph and the original source dataframe should update with a value for example "OUTLIER" only the selected points please. Maybe if was possible, any idea with another library ? The original code for select, from the library of Altair is this, this code selection and update a table, but doesnt allow to export in a new dataframe import altair as alt from vega_datasets import data

source = data.cars()

Brush for selection

brush = alt.selection_interval()

Scatter Plot

points = alt.Chart(source).mark_point().encode( x='Horsepower:Q', y='Miles_per_Gallon:Q', color=alt.condition(brush, alt.value('steelblue'), alt.value('grey')) ).add_params(brush)

Base chart for data tables

ranked_text = alt.Chart(source).mark_text(align='right').encode( y=alt.Y('row_number:O').axis(None) ).transform_filter( brush ).transform_window( row_number='row_number()' ).transform_filter( alt.datum.row_number < 15 )

Data Tables

horsepower = ranked_text.encode(text='Horsepower:N').properties( title=alt.Title(text='Horsepower', align='right') ) mpg = ranked_text.encode(text='Miles_per_Gallon:N').properties( title=alt.Title(text='MPG', align='right') ) origin = ranked_text.encode(text='Origin:N').properties( title=alt.Title(text='Origin', align='right') ) text = alt.hconcat(horsepower, mpg, origin) # Combine data tables

Build chart

alt.hconcat( points, text ).resolve_legend( color="independent" ).configure_view( stroke=None ) Image

Have you considered any alternative solutions?

No response

mattijn commented 1 month ago

Thanks for your request. This is already possible using the alt.JupyterChart method, see: https://altair-viz.github.io/user_guide/jupyter_chart.html#observing-selections. Closing this issue as it is not actionable. If you face any issues with the examples in the mentioned link, please raise a new issue. Thanks again for this request!