python - 如何使用 Bokeh 动态隐藏字形和图例项

Question

我正在尝试在 Bokeh 中实现复选框，其中每个复选框应显示/隐藏与其关联的行。我知道可以通过图例来实现此目的，但我希望这种效果同时在两个图中发生。此外，图例也应该更新。在下面的示例中，出现了复选框，但不执行任何操作。我显然不明白如何更新用作源的数据框。感谢您的帮助。

from bokeh.io import show, curdoc
from bokeh.models import  HoverTool, ColumnDataSource, Legend
from bokeh.plotting import figure
from bokeh.palettes import Category10
from bokeh.models.widgets import CheckboxGroup
from bokeh.layouts import row
import pandas as pd

def update(atrr, old, new):
        lines_to_plot = [checkbox_group.labels[i] for i in checkbox_group.active]
        cols = ['x']
        for label in lines_to_plot:
            cols += [label + 'y']
            cols += [label]
        newdf = df0[cols] 
        source.data.update(ColumnDataSource(newdf))    

df0 = pd.DataFrame({'x': [1, 2, 3], 'Ay' : [1, 5, 3], 'A': [0.2, 0.1, 0.2], 'By' : [2, 4, 3], 'B':[0.1, 0.3, 0.2]})

columns = ['A', 'B']
checkbox_group = CheckboxGroup(labels=columns, active=[0, 1])

tools_to_show = 'box_zoom,save,hover,reset'
p = figure(plot_height =300, plot_width = 1200, 
           toolbar_location='above',
           tools=tools_to_show)

legend_it = []
color = Category10[10]
columns = ['A', 'B']
source = ColumnDataSource(df0)
for i, col in enumerate(columns):
    c = p.line('x', col, source=source, name=col, color=color[i])
    legend_it.append((col, [c]))


legend = Legend(items=legend_it, location=(5,114))#(0, -60))

p.add_layout(legend, 'right')

hover = p.select(dict(type=HoverTool))
hover.tooltips = [("Name","$name"), ("Aux", "@$name")]
hover.mode = 'mouse'

layout = row(p,checkbox_group)

checkbox_group.on_change('active', update)

curdoc().add_root(layout)

Answer 1

您必须手动管理 LegendItem 对象。这是一个完整的示例:

import numpy as np

from bokeh.io import curdoc
from bokeh.layouts import row
from bokeh.palettes import Viridis3
from bokeh.plotting import figure
from bokeh.models import CheckboxGroup, Legend, LegendItem

p = figure()
props = dict(line_width=4, line_alpha=0.7)
x = np.linspace(0, 4 * np.pi, 100)
l0 = p.line(x, np.sin(x), color=Viridis3[0], **props)
l1 = p.line(x, 4 * np.cos(x), color=Viridis3[1], **props)
l2 = p.line(x, np.tan(x), color=Viridis3[2], **props)

legend_items = [LegendItem(label="Line %d" % i, renderers=[r]) for i, r in enumerate([l0, l1, l2])]
p.add_layout(Legend(items=legend_items))

checkbox = CheckboxGroup(labels=["Line 0", "Line 1", "Line 2"], active=[0, 1, 2], width=100)

def update(attr, old, new):
    l0.visible = 0 in checkbox.active
    l1.visible = 1 in checkbox.active
    l2.visible = 2 in checkbox.active
    p.legend.items = [legend_items[i] for i in checkbox.active]

checkbox.on_change('active', update)

layout = row(checkbox, p)
curdoc().add_root(layout)