如何在Bokeh中使用customjs动态更新下拉菜单选项

Question

我正在尝试通过使用Bokeh中的customjs回调，根据用户在上一个下拉菜单中所做的选择来更新下拉菜单。在下面的示例中，用户可以基于选择common_name来创建基本图，也可以通过选择四边形来创建基本图。但是我希望用户能够首先选择一个common_name，然后根据可用于该common_name的数据（即基于首先选择的common_name）选择一个Quadrat。有什么想法吗？

from bokeh.models import CustomJS, ColumnDataSource, MultiSelect, Column

from bokeh.plotting import figure, show
from bokeh.layouts import row, column
import pandas as pd

# data
data = dict(common_name = ['A','A','B','C','B','B','A','C','C','B','A','B','C'],
length = [10, 20, 10, 20, 30, 20, 20, 30, 20, 30, 30, 20, 30],
weight = [100, 200, 100, 300, 100, 400, 100, 300, 100, 400, 500, 600, 450],
quadrat = ['N', 'N', 'N', 'N', 'M', 'M', 'M', 'M', 'O', 'O', 'M', 'N', 'O'])

data = pd.DataFrame(data)

data_source = ColumnDataSource(data)

# Empty source so the plot is empty before data is selected
source = ColumnDataSource(dict(length = [], weight = []))

plot = figure()

plot.circle(x = 'length', y = 'weight', source = source)


# Select species
available_species = list(set(data['common_name']))
available_species.sort()

species_callback = CustomJS(args = {'source': source, 'data_source': data_source},
code = """
var data = data_source.data;
var source_data = source.data;
var common_name = data['common_name'];
var selected_species = cb_obj.value;
var length_data = data['length'];
var weight_data = data['weight'];
var length = source_data['length'];
length.length = 0;
var weight = source_data['weight'];
weight.length = 0;
 for (var i = 0; i < length_data.length; i++) {
  if (selected_species.indexOf(common_name[i]) >= 0) {
   length.push(length_data[i]);
   weight.push(weight_data[i]);
    }
  }
  source.change.emit();
  """)

multiselect_species = MultiSelect(title = 'Species:', value = [], options = available_species, width = 240)


# Select quadrat
available_quadrat = list(set(data['quadrat']))
available_quadrat.sort()

quadrat_callback = CustomJS(args = {'source': source, 'data_source': data_source},
code = """
var data = data_source.data;
var source_data = source.data;
var quadrat = data['quadrat'];
var selected_quadrat = cb_obj.value;
var length_data = data['length'];
var weight_data = data['weight'];
var length = source_data['length'];
length.length = 0;
  var weight = source_data['weight'];
  weight.length = 0;
  for (var i = 0; i < length_data.length; i++) {
    if (selected_quadrat.indexOf(quadrat[i]) >= 0) {
      length.push(length_data[i]);
      weight.push(weight_data[i]);
    }
  }
  source.change.emit();
  """)

multiselect_quadrat = MultiSelect(title = 'Set:', value = [], options = available_quadrat, width = 240)
multiselect_quadrat.js_on_change('value', quadrat_callback)

multiselect_species.js_on_change('value', species_callback, CustomJS(args = dict(multiselect_quadrat = multiselect_quadrat,
                                                                                 available_quadrat = available_quadrat),
code="""
const available_quadrat = %s
multiselect_quadrat.options = "available_quadrat[cb_obj.value]"
""" % available_quadrat))

  # Set up widgets layout
widgets_layout = column(multiselect_species, multiselect_quadrat)

page_layout = row(widgets_layout, plot)

show(page_layout)

Answer 1

下面是一个完整的示例，该示例基于另一个小部件的MultiSelect回调来更新CustomJS：

from bokeh.io import show
from bokeh.layouts import column
from bokeh.models import RadioButtonGroup, CustomJS, MultiSelect

opts = {
    0: ["foo", "bar"],
    1: ["baz", "quux"],
}

bg = RadioButtonGroup(labels=["Stuff", "Things"], active=0)

ms = MultiSelect(options=opts[0])

bg.js_on_change('active', CustomJS(args=dict(ms=ms), code="""
    const opts = %s
    ms.options = opts[cb_obj.active]
""" % opts))

show(column(bg, ms)