如何在散景中只绘制一个乐队？

Question

Bokeh 1.0.1

python 3.6.6

I'd like to plot a simple Band using Bokeh. Here's a minimal example:

from bokeh.plotting import (output_notebook, figure, show,
        ColumnDataSource)

from bokeh.models import Band

output_notebook()

p = figure()

source = ColumnDataSource({
        'base':[0,1,2,3],
        'lower':[1,2,3,4],
        'upper':[8,6,8,6]
        })

band = Band(base='base', lower='lower', upper='upper', 
            source=source, fill_alpha=0.5)

p.add_layout(band)
#p.scatter(x=[2,3,4], y=[5,6,8])

show(p)

This produces an empty graph (ie, it doesn't plot the Band):

There are no errors when running the code. BUT if I uncomment the line #p.scatter(x=[2,3,4], y=[5,6,8]) , my band shows up (along with some scatter points that I don't actually want). How can I plot only a Band?

Answer 1

By default, Bokeh plots have auto-ranges that configure to fit the data. But that only applies to data glyphs like circle , etc. It does not consider annotations such as Band . So when you plot without any glyph, Bokeh does not know what to set the range values to, because there is no glyph data to consider. To plot just a band, you will have to set the ranges explicitly, eg:

p = figure(x_range=(0,5), y_range=(0, 10))