bokeh の tooltip で　@foo,@bar　とは何でしょうか？


bokeh の tooltip で @foo,@bar はどのような使い方をするのでしょうか？  
ご指導よろしくお願いいたします。



[code]

        tooltips=[
            ("(x,y)", "($x, $y)"),
            ("date", "@date{%F %R}"), # '%Y-%m-%d %H:%M'
            ("sales", "@sales")
        ]
    
[/code]

`@`から始まるフィールドは、`ColumnDataSource`のcolumnと紐づいています。

> Field names that begin with @ are associated with columns in a
> ColumnDataSource. For instance the field name "@price" will display values
> from the "price" column whenever a hover is triggered. If the hover is for
> the 17th glyph, then the hover tooltip will correspondingly display the 17th
> price value.

<https://bokeh.pydata.org/en/latest/docs/user_guide/tools.html#basic-tooltips>
引用



[code]

        tooltips=[
            ("(x,y)", "($x, $y)"),
            ("date", "@date{%F %R}"), # '%Y-%m-%d %H:%M'
            ("sales", "@sales")
        ]
    
[/code]

`@`から始まるフィールドは、`ColumnDataSource`のcolumnと紐づいています。

> Field names that begin with @ are associated with columns in a
> ColumnDataSource. For instance the field name "@price" will display values
> from the "price" column whenever a hover is triggered. If the hover is for
> the 17th glyph, then the hover tooltip will correspondingly display the 17th
> price value.

<https://bokeh.pydata.org/en/latest/docs/user_guide/tools.html#basic-tooltips>
引用

