Question

我有一个由“ select”更新的ColumnDataSource-具体来说，注册了一个回调，该回调在for循环上迭代，并且仅推送匹配的值。最后，我使用change.emit（）发出更改。但是，它似乎没有更新基础的ColumnDataSource吗？

稍后使用第二个回调（链接到下载按钮并调用下载脚本）时，它应获取所有已过滤的columnDataSource并允许用户下载。但是，它总是下载初始化的ColumnDataSource，而不是根据用户输入更新的内容。

我怎么能...

保存第一个回调的cb_obj（这样可以将其解析为第二个回调，并且可以再次执行相同的过滤-看起来有点浪费吗？）
正确地将过滤后的ColumnDataSource传递给第二个回调。

非常感谢您的帮助。

编辑：我意识到这是在发生，因为我将ColumnDataSource和Button输出为不同的组件-这似乎破坏了两者之间的关系（测试是否可以将它们放入其中同一组组件）。无论如何，在保持关系的同时（我想在将它们嵌入网站的位置上具有完全的灵活性，即不使用Bokeh的预定义布局选项）是完全可以做到的？

    from bokeh.io import output_file, show
from bokeh.layouts import widgetbox, row, column
from bokeh.models.widgets import Select, DataTable, TableColumn, Button
from bokeh.models.sources import ColumnDataSource, CDSView
from bokeh.models import CustomJS
from bokeh.io import show, output_file, output_notebook


select = Select(title="Animal", options=["All","Cat","Dog"])

button = Button(label="Download", button_type="success")

source=ColumnDataSource(data=dict(Animal=["Cat","Cat","Cat","Cat","Dog","Dog","Dog","Dog",],Breed=["Siamese","Persian","Bengal","Burmese","Lab","Golden", "Poodle","Pug"]))
filtered=ColumnDataSource(data=dict(Animal=["Cat","Cat","Cat","Cat","Dog","Dog","Dog","Dog",],Breed=["Siamese","Persian","Bengal","Burmese","Lab","Golden", "Poodle","Pug"]))

columns = [TableColumn(field="Animal",title="Animal"),
           TableColumn(field="Breed",title="Breed",sortable=True)]

data_table_filtered=DataTable(source=filtered,columns=columns, width=800 )

dropDown=ColumnDataSource(data=dict(dropDown=[""]))

callback = CustomJS(args=dict(filtered=filtered, unfiltered=source,
                              data_table_filtered=data_table_filtered, dropDown=dropDown), code="""
var data = unfiltered.data;
var f = cb_obj.value;

if(f != 'All') {
    var newSource = filtered.data;
    newSource['Animal']=[]
    newSource['Breed']=[]

    for(i = 0; i < data['Animal'].length;i++){

        if(data['Animal'][i]==f){

            newSource['Animal'].push(data['Animal'][i])
            newSource['Breed'].push(data['Breed'][i])
        }
    }
}
else{
    var newSource = filtered.data;
    newSource['Animal']=[]
    newSource['Breed']=[]
    for(i = 0; i < data['Animal'].length;i++){
            newSource['Animal'].push(data['Animal'][i])
            newSource['Breed'].push(data['Breed'][i])
            }
}

filtered.change.emit()
// trigger change on datatable
data_table_filtered.change.emit()

""")

select.js_on_change('value',callback)

button.callback = CustomJS(args=dict(filtered=filtered),
                       code=open(join(dirname(__file__), "download.js")).read())

wg = widgetbox(select,data_table_filtered)
wg1 = widgetbox(button)

script, div = components(wg)
script1, div1 = components(wg1)

return script,div,script1,div1

download.js：

var data = filtered.data;
console.log(data)
var filetext = 'Animal,Breed\n';
for (var i = 0; i < data['Animal'].length; i++) {
    var currRow = [data['Animal'][i].toString(),
                   data['Breed'][i].toString().concat('\n')];

    var joined = currRow.join();
    filetext = filetext.concat(joined);
}

var filename = 'data_result.csv';
var blob = new Blob([filetext], { type: 'text/csv;charset=utf-8;' });

//addresses IE
if (navigator.msSaveBlob) {
    navigator.msSaveBlob(blob, filename);
} else {
    var link = document.createElement("a");
    link = document.createElement('a')
    link.href = URL.createObjectURL(blob);
    link.download = filename
    link.target = "_blank";
    link.style.visibility = 'hidden';
    link.dispatchEvent(new MouseEvent('click'))
}

解析到第二个回调函数时，列数据源似乎未更新

0 个答案: