选择DropDown无法使用JS回调更改ColumnDataSource

Question

I have tried changing multiple parameters(arguments) but this doesn't work.

The bokeh version is 1.3.4.

from bokeh.layouts import column
from bokeh.layouts import column
from bokeh.models import CustomJS, ColumnDataSource, Slider, Select
from bokeh.plotting import Figure, output_notebook, show
import numpy as np
a = 20


bokeh_tools = "pan,wheel_zoom"

output_notebook()
plot_2s = ColumnDataSource(data=dict(x=[1, 2, 3], y=[1, 2, 3]))
plot_3s = ColumnDataSource(data=dict(x=[3, 4, 5], y=[1, 2, 3]))
line_source = ColumnDataSource(data=dict(x=[1, 2, 3], y=[1, 2, 3]))

plot_1 = figure(x_axis_type="datetime", plot_width=800, tools=bokeh_tools, title="plot_1")
plot_1.line(x = 'x', y='y', source=plot_2s)
plot_2 = figure(x_axis_type="datetime", plot_width=800, tools=bokeh_tools, title="plot_2")
plot_2.line(x='x', y='y', source=line_source)

select = Select(title="SELECT", options=["val1", "val2"])
column = column(select, plot_2)
show(column)

select.callback = CustomJS(args={"cds2": plot_2s, "cds3": plot_3s, "ls": line_source}, code="""
         if(cb_obj.value === "val1"){ 
                 ls.data = cds2.data;
         }else if(cb_obj.value === "val2"){
                 ls.data = cds3.data;
         }
         ls.change.emit();
         """)

There are no error message the callback is not implemented

Answer 1

You callback is never executed, because it is never added to the output. As soon as you call show the HTML output is generated and displayed. Anything after that point is effectively a no-op, and does not exist as far as the output is concerned. Typically show should be called last.