Shiny

Shiny#

Using ITable in Shiny#

The recommended way to use ITables in a Shiny for Python application is with the ITable Widget.

In the Shiny Express syntax this is as simple as:

from shinywidgets import render_widget

from itables.widget import ITable


@render_widget
def my_table():
    """
    This function creates the "my_table" widget.
    """
    # Note: df is an optional argument
    return ITable(caption="A table rendered with ITable")

In the Shiny Core syntax you will need, in addition to the above, to insert the table in the UI with output_widget:

from shiny import ui
from shinywidgets import output_widget

app_ui = ui.page_fluid(
    # ...
    output_widget("my_table"),
    # ...
)

Updating the widget#

Rather than re-creating the widget each time the data changes, you can call the .update method of the widget object, using the @reactive.effect decorator:

from shiny import reactive
from shiny.express import input

from itables.sample_dfs import get_dict_of_test_dfs

dfs = get_dict_of_test_dfs()


@reactive.effect
def _():
    """
    This "reactive.effect" calls the "update" method of the ITable widget
    to update the widget with the new inputs.
    """
    # Get the new inputs
    df = dfs[input.table_selector()]
    selected_rows = list(range(0, len(df), 3))

    # Update the widget
    my_table.widget.update(df, selected_rows=selected_rows)

Accessing the selected_rows attribute#

The reactive_read function lets you access the selected_rows attribute of the ITable object. The code below displays the selected rows:

from shiny.express import render
from shinywidgets import reactive_read


@render.code
def selected_rows():
    """
    Here we read the "selected_rows" attribute of the ITable widget
    """
    return str(reactive_read(my_table.widget, "selected_rows"))

An example application#

This repository contains a simple example of a Shiny application that uses the ITable widget.

The source code of the application is at app.py (Shiny Express) or app-core.py (Shiny Core).

Limitations#

Compared to show, the ITable widget has the same limitations as the Streamlit component, e.g. structured headers are not available, you can’t pass JavaScript callback, etc.

The good news is that if you only want to display the table, you do not need the ITable widget. You can render the table using HTML(DT(...)) as here:

from shiny import ui

from itables.sample_dfs import get_countries
from itables.shiny import DT, init_itables

# Load the datatables library and css from the ITables package
# (use connected=True if you prefer to load it from the internet)
ui.HTML(init_itables())

# Render the table with DT
ui.HTML(DT(get_countries(html=False)))

An example for an application that uses DT is available at app.py (Shiny Express) or app-core.py (Shiny Core).

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