bokeh `figure.renderers` 的一个元素的 `_property_values` 如何直接改变？

Question

散景figure.renderers的某个元素的_property_values如何直接改变？我了解到 renderers 的元素有一个 id，所以我希望做类似 renderers['12345'] 的事情。但因为它是一个列表（更准确地说是一个 PropertyValueList），所以这是行不通的。相反，我找到的唯一解决方案是遍历列表，将正确的元素存储在新指针（？）中，修改指针，从而修改原始元素。

这是我的玩具示例，其中直方图中的垂直线根据某些小部件的值进行更新：

import hvplot.pandas
import ipywidgets as widgets
import numpy as np
from bokeh.io import push_notebook, show, output_notebook
from bokeh.models import Span
from bokeh.plotting import figure

%matplotlib inline

hist, edges = np.histogram([1, 2, 2])

p = figure()
r = p.quad(top=hist, bottom=0, left=edges[:-1], right=edges[1:])
vline = Span(location=0, dimension='height')
p.renderers.extend([vline])

def update_hist(x):    
    myspan = [x for x in p.renderers if x.id==vline.id][0]
    myspan._property_values['location'] = x
    show(p, notebook_handle=True)

widgets.interact(update_hist, x = widgets.FloatSlider(min=1, max=2))

Answer 1

Bigreddot pointed me into the right direction: I don't have to update p directly, but the elements used to generate p (here the Span). By this I found the 代码所在解决方案：更新vline.location.

完整代码：

import hvplot.pandas
import ipywidgets as widgets
import numpy as np
from bokeh.io import push_notebook, show, output_notebook
from bokeh.models import Span
from bokeh.plotting import figure

%matplotlib inline

hist, edges = np.histogram([1, 2, 2])

p = figure()
r = p.quad(top=hist, bottom=0, left=edges[:-1], right=edges[1:])
vline = Span(location=0, dimension='height')
p.renderers.extend([vline])
show(p, notebook_handle=True)

def update_hist(x):    
    vline.location = x
    push_notebook()

widgets.interact(update_hist, x = widgets.FloatSlider(min=1, max=2, step = 0.01))

作为一个 Python 初学者，我仍然经常监督 Python does not have variables。所以我们可以通过改变 y.

来改变一个元素 x

x = ['alice']
y = x
y[0] = 'bob'
x  # is now ['bob] too

bokeh `figure.renderers` 的一个元素的 `_property_values` 如何直接改变？

How can the `_property_values` of an element of a bokeh `figure.renderers` be changed directly?

python-3.x

bokeh

updates

ipywidgets