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Archived discussions · Captured October 28, 2026

CategoricalSlider shows 'undefined' value and skip that value

Community Supportbokeh
poltricerri
poltricerri

I am creating a CategoricalSlider as follows:

elements = [ list of integer values from 2 to 2^31 ]
XRange = CategoricalSlider(title=“X axis range”, value=str(16777216), categories=[str(el) for el in elements])

The ref value of 16777216 ( 2^24) is correctly shown at start of the bokeh app but when I slide the slider to select other values in the list of categories, when I am trying to pass on the 16777216 value, the tool shows ‘undefined’ and my function update() to update the graph is not shown. The same behaviour is observed for other values.

Please not that the slider displays correctly the value below 16777216 and above.

I have tried to put my graph and my slider on two different rows of the layout thinking it was a rendering issue, but I got the same behaviour.

MWE:

from bokeh.models import CategoricalSlider
from bokeh.plotting import show
from bokeh.layouts import column

els = [2, 4, 8, 10, 16, 32, 64, 100, 128, 185, 225, 256, 512, 1000, 1024, 2048, 4096, 8192, 10000, 16384, 24000, 32768, 44000, 56000, 65536, 100000, 131072, 262144, 524288, 1000000, 1048576, 2097152, 4194304, 8388608, 10000000, 16777216, 33554432, 67108864, 100000000, 134217728, 268435456, 390000000, 536870912, 810000000, 1000000000, 1073741824]

XRange = CategoricalSlider(title="X axis range", value=str(16777216), categories=[str(el) for el in els])


inputs = column([XRange], width=320, height=800)

layout = column(inputs)

show(layout)

slider

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