Beginner needs help with live Table

Dash Python
1

Hi everybody,

I’m new in Plotly and I need your help. My Idea is a Datatable with a live update every 2min. I’m started with this example here: https://dash.plotly.com/datatable
Ok, it works. I get Data from my csv-file. But how do I get the table to update automatically?

I’ve read any websites with examples on a dcc-object. But, I have not found an example with a Table.

Please give me a hint or an example with this…

Best Regards
Torsten

2

Hi @Torsten

For updating any Dash component (like a table) you need to add a dcc.Interval in the layout (in any part of the layout), and use the property n_intervals as Input in a callback, everytime the n_intervals change the callback will be executed.
Inside the callback build your table and return it to any html.Div in the layout.

Example of a layout with html.Div and dcc.Interval:

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.layout = html.Div(
    html.Div([
        html.Div(id='output'),
        dcc.Interval(
            id='interval-component',
            interval=1*1000, # in milliseconds
            n_intervals=0
        )
    ])
)

Example of a callback:

@app.callback(Output('output', 'children'),
              Input('interval-component', 'n_intervals'))
def update(n):

    # bild here the table you want to show
    table = dash_table.DataTable( ....

    return table

Here you will find the documentation about dcc.Interval:
https://dash.plotly.com/live-updates

3

Hi Eduardo,

Thanks for your response. I have updated my code which looks like this:

import dash
import dash_table
import pandas as pd
import dash_html_components as html
import dash_core_components as dcc
from dash.dependencies import Output, Input

app = dash.Dash(__name__)

app.layout = html.Div([         #    html.H4('Data Live Feed'),
    html.Div(id='output'),
    dcc.Interval(
        id='interval-component',
        interval = 3*1000,
        n_intervals=0)])


@app.callback(Output('output', 'children'),
              Input('interval-component', 'n_intervals'))
def update_Table():
    df = pd.read_csv(r'C:\Users\freydtt\Programmierung\Python\mydata.csv')
    table =  dash_table.DataTable(
        id='table',
        columns=[{"name": i, "id": i} for i in df.columns],
        data=df.to_dict('records'))
    return table




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

The Update-Request works fine.

Thanks…

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