Dash DataTable - Updating the Number of Rows

[chriddyp]

@Stuart_Kerkhof

Could someone shed some light on the ‘Error Loading Dependancies’ error?

This is a generic error that usually corresponds to a malformed response from a callback or from app.layout. Sometimes you can learn more about this error by inspecting your terminal or your browser’s console, but not always.

@Stuart_Kerkhof

Because the DataTable is outputted to ‘children’ of an empty html.Div, the data can only be accessed via this ‘children’ property, instead of the much more beautiful prop ‘rows’.

Hm, you should be able to access the rows property even if the table is generated dynamically. Here is a simple example:

import dash
from dash.dependencies import Input, Output
import dash_html_components as html
import dash_core_components as dcc
from dash_table_experiments import DataTable
import json

app = dash.Dash()
app.config['suppress_callback_exceptions'] = True
app.layout = html.Div([
    html.Button(id='button', n_clicks=0, children='Show table'),
    html.Div(id='content'),
    html.Div(DataTable(rows=[{}]), style={'display': 'none'})
])


@app.callback(Output('content', 'children'), [Input('button', 'n_clicks')])
def display_output(n_clicks):
    if n_clicks > 0:
        return html.Div([
            html.Div(id='datatable-output'),
            DataTable(
                id='datatable',
                rows=[{'Column 1': i} for i in range(5)]
            )
        ])


@app.callback(
    Output('datatable-output', 'children'),
    [Input('datatable', 'rows')])
def update_output(rows):
    return html.Pre(
        json.dumps(rows, indent=2)
    )


if __name__ == '__main__':
    app.run_server(debug=True)