如何在 JavaScript Python 的 Bokeh 回调中更新源？

Question

我正在改编 for my case, where I want an interactive, standalone graph where the slider selects which column of the data to plot in a bar chart. (Standalone is crucial, I cannot run a Bokeh server, thus the need for JavaScript callbacks。)

数据是一个矩形的浮点数，38 列中的每一列有 100 行，它们都有字符串标签，如 '40' 等。（这就是 pandas .read_csv() 处理的方式默认情况下 header 中的数字。）这是左上角的示例（3x3，加上行和列标签）：

        # ,        40,        41,        42,
   1.00000,   1.00000,   0.99287,   0.98489,
   2.00000,   1.00000,   0.99348,   0.98626,
   3.00000,   1.00000,   0.99433,   0.98922,

下面的代码生成第一列的图表，但不会在移动滑块时更新图表。

通过查看它，我怀疑问题出在 JavaScript 代码上，尽管 ColumnDataSource 对我来说仍然有点神秘。（数字列标签到列中数字列表的更直接的字典不能像 datasource_available 那样工作，尽管对应于链接答案的用例。）

datadf = pd.read_csv('male_survival_by_pctile.csv')
datadf.set_index('# ',inplace=True)
years = range(40,77)
data = {}
data_available = {}

for year in years:
    data[year] = {'top':datadf[str(year)],'x':range(1,101)}
data_available = ColumnDataSource.from_df(datadf)

from bokeh.core.properties import field
from bokeh.io import curdoc, output_notebook, show
from bokeh.layouts import layout, column
from bokeh.models import (ColumnDataSource, HoverTool, SingleIntervalTicker,
                          Slider, Button, Label, CustomJS)
from bokeh.plotting import figure

output_notebook()

source_visible = ColumnDataSource(data=dict(x=range(1,101),top=data_available[str(years[0])]))
source_available = ColumnDataSource(data=data_available)

plot = figure(output_backend="webgl")
plot.xaxis.ticker = SingleIntervalTicker(interval=.01)
plot.xaxis.axis_label = "Income percentile"
plot.yaxis.ticker = SingleIntervalTicker(interval=.05)
plot.yaxis.axis_label = "Survival rate"

label = Label(x=1.1, y=18, text=str(years[0]), text_font_size='70pt', text_color='#eeeeee')
plot.add_layout(label)

plot.vbar(top='top',x='x',width=1,source=source_visible)

slider = Slider(start=years[0], end=years[-1], value=years[0], step=1, title="Age")

slider.callback = CustomJS(
    args=dict(source_visible=source_visible,
              source_available=source_available), code="""
        var selected_function = cb_obj.get('value').toString();
        // Get the data from the data sources
        var data_visible = source_visible.get('data');
        var data_available = source_available.get('data');
        // Change bar height to the selected value
        data_visible.top = data_available[selected_function];
        // Update the plot
        source_visible.trigger('change');
    """)

layout = column(slider, plot)

show(layout)

Answer 1

如您所料，问题出在 CustomJS 代码中。有两件事需要修复。

Bokeh 已弃用 get() 和 set() 方法，并用 getv() 或 setv() 取而代之。但是，访问或修改模型属性的首选方法是通过常用的 JavaScript 属性，例如 source_visible.data.
Bokeh 有 deprecated trigger('change') 并替换为 change.emit()。

固定CustomJS代码：

slider.callback = CustomJS(
    args=dict(source_visible=source_visible,
              source_available=source_available), code="""
        var selected_function = cb_obj.value.toString();
        // Get the data from the data sources
        var data_visible = source_visible.data;
        var data_available = source_available.data;
        // Change bar height to the selected value
        data_visible.top = data_available[selected_function];
        // Update the plot
        source_visible.change.emit();
    """)

JavaScript 错误和警告出现在浏览器的控制台中。 Here are instructions for opening the console in different browsers.

如何在 JavaScript Python 的 Bokeh 回调中更新源？

How to update a source in a JavaScript Callback of Bokeh in Python?

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