Title: Point Selection1D stream example#
Description: A linked streams example demonstrating how to use Selection1D to get currently selected points and dynamically compute statistics of selection.
import numpy as np import holoviews as hv from holoviews import opts from holoviews import streams hv.extension('bokeh')
opts.defaults(opts.Points(tools=['box_select', 'lasso_select'])) # Declare some points points = hv.Points(np.random.randn(1000,2 )) # Declare points as source of selection stream selection = streams.Selection1D(source=points) # Write function that uses the selection indices to slice points and compute stats def selected_info(index): selected = points.iloc[index] if index: label = 'Mean x, y: %.3f, %.3f' % tuple(selected.array().mean(axis=0)) else: label = 'No selection' return selected.relabel(label).opts(color='red') # Combine points and DynamicMap points + hv.DynamicMap(selected_info, streams=[selection])
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