Getting selection source from heatmap with tap and hover

hvPlot
1

I can’t figure out how to access the hover data or the tap data from an hvplot heatmap.

I’m trying:

hv.streams.SelectionXY(source=heatmap)

hv.streams.Selection1D(source=heatmap)

hv.streams.Tap(source=heatmap)

Creating the heatmap with:

heatmap = similarities.T.hvplot.heatmap(title="Question Similarities", cmap='Reds', rot=60, **DEFAULT_HV_OPTS).opts(tools=['hover','tap'])
heatmap

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image1378×428 44.8 KB

2

This is how I’m trying to use it:

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image1419×673 65.2 KB

3

Have you seen this example?
https://holoviews.org/reference/streams/bokeh/Tap.html

4

It’s not working.

image
image1407×700 87.3 KB

5

Thanks for testing; can you provide that as a code snippet that I can easily copy and paste (preferably with some sample/random data)

6

Sure.

import numpy as np
import pandas as pd
import hvplot.pandas

df = pd.DataFrame({'x':['a','b','c'],'y':[1,2,3],'v':[0.1,0.2,0.3]})

heatmap = df.hvplot.heatmap(x='x',y='y',C='v')

stream = hv.streams.Tap(source=heatmap, x=np.nan, y=np.nan)

# make a function that displays the location when called.
def location(x, y):
    """Display pane showing the x and y values"""
    return pn.pane.Str('Click at %f, %f' % (x, y), width=200)

# Display the points and the function output, updated
# whenever the stream values change
layout = pn.Column(heatmap, pn.bind(location, x=stream.param.x, y=stream.param.y))
# display the container
layout
7

Using f’strings work; previously, x and y were passed as strings but %f expects floats.

import numpy as np
import pandas as pd
import holoviews as hv
import panel as pn
import hvplot.pandas
pn.extension()

df = pd.DataFrame({'x':['a','b','c'],'y':[1,2,3],'v':[0.1,0.2,0.3]})

heatmap = df.hvplot.heatmap(x='x',y='y',C='v')

stream = hv.streams.Tap(source=heatmap, x=np.nan, y=np.nan)

# make a function that displays the location when called.
def location(x, y):
    """Display pane showing the x and y values"""
    return pn.pane.Str(f'Click at {x}, {y}', width=200)

# Display the points and the function output, updated
# whenever the stream values change
layout = pn.Column(heatmap, pn.bind(location, x=stream.param.x, y=stream.param.y))
# display the container
layout
2 Likes
8

Oh wow that’s crazy… thanks!

1 Like