dash_simple_example_pandas_datareader.py

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

from pandas_datareader import data as web
from datetime import datetime as dt

app = dash.Dash('Hello World')

app.layout = html.Div([
    dcc.Dropdown(
        id='my-dropdown',
        options=[
            {'label': 'Coke', 'value': 'COKE'},
            {'label': 'Tesla', 'value': 'TSLA'},
            {'label': 'Apple', 'value': 'AAPL'}
        ],
        value='COKE'
    ),
    dcc.Graph(id='my-graph')
], style={'width': '500'})

@app.callback(Output('my-graph', 'figure'), [Input('my-dropdown', 'value')])
def update_graph(selected_dropdown_value):
    df = web.DataReader(
        selected_dropdown_value,
        'google',
        dt(2017, 1, 1),
        dt.now()
    )
    return {
        'data': [{
            'x': df.index,
            'y': df.Close
        }],
        'layout': {'margin': {'l': 40, 'r': 0, 't': 20, 'b': 30}}
    }

app.css.append_css({'external_url': 'https://codepen.io/chriddyp/pen/bWLwgP.css'})

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

found that this example works only after following dependencies are installed:
pip install plotly==2.0.11 pip install dash==0.17.5 pip install dash_renderer pip install dash_html_components pip install pandas_datareader

For more about how this example works and how to install the necessary dependencies, please see the official dash user guide at https://dash.plot.ly. Thank you!

The user guide instructions for the installation at https://plot.ly/dash is very specific about which version of each library to install. Do you know if we could just install those libraries without specifying the version?

@PierreBourgault You could install without version numbers - it works for the current setup . But may fail in the future.

Am I the only that gets an error like this when running the example? The error seems to be from fetching the data to plot.
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xf8 in position 359: invalid start byte`

It looks like Google problem, try yaho. Work fine for me
df = web.DataReader(
selected_dropdown_value,
'yahoo',
dt(2017, 1, 1),
dt.now()
)

how to run a dash application can anybody tell me coz i am getting an error while running the code on jupyter i.e. system exit and also tell me from where i can access the app

Not 'google' nor 'yahoo' is currently working, please provide some valid source

you can use quandl instead , ex below 👍

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

from pandas_datareader import data as web
from datetime import datetime as dt
import quandl

app = dash.Dash('Hello World')

app.layout = html.Div([
dcc.Dropdown(
id='my-dropdown',
options=[
{'label': 'Poxel', 'value': 'EURONEXT/POXEL'},
{'label': 'Orange', 'value': 'EURONEXT/ORA'},
{'label': 'TechnipFMC', 'value': 'EURONEXT/FTI'}
],
value='Poxel'
),
dcc.Graph(id='my-graph')
], style={'width': '500'})

@app.callback(Output('my-graph', 'figure'), [Input('my-dropdown', 'value')])
def update_graph(selected_dropdown_value):
df = quandl.get(
selected_dropdown_value,
authtoken="your_access_token_after_registering_to_quandl"
)
return {
'data': [{
'x': df.index,
'y': df.Last
}],
'layout': {'margin': {'l': 40, 'r': 0, 't': 20, 'b': 30}}
}

app.css.append_css({'external_url': 'https://codepen.io/chriddyp/pen/bWLwgP.css'})

if name == 'main':
app.run_server()

It works

Installed all dependencies, but I get the following error from my jupyter lab.
Using pipenv with Google Cloud VM & Ubuntu 16.04
Thanks,

UnsupportedOperation Traceback (most recent call last)
in ()
37
38 if name == 'main':
---> 39 app.run_server()

~/.local/share/virtualenvs/simulation-RVBo82bs/lib/python3.6/site-packages/dash/dash.py in run_server(self, port, debug, **flask_run_options)
566 debug=False,
567 **flask_run_options):
--> 568 self.server.run(port=port, debug=debug, **flask_run_options)

~/.local/share/virtualenvs/simulation-RVBo82bs/lib/python3.6/site-packages/flask/app.py in run(self, host, port, debug, load_dotenv, **options)
936 options.setdefault('threaded', True)
937
--> 938 cli.show_server_banner(self.env, self.debug, self.name, False)
939
940 from werkzeug.serving import run_simple

~/.local/share/virtualenvs/simulation-RVBo82bs/lib/python3.6/site-packages/flask/cli.py in show_server_banner(env, debug, app_import_path, eager_loading)
627 message += ' (lazy loading)'
628
--> 629 click.echo(message)
630
631 click.echo(' * Environment: {0}'.format(env))

~/.local/share/virtualenvs/simulation-RVBo82bs/lib/python3.6/site-packages/click/utils.py in echo(message, file, nl, err, color)
257
258 if message:
--> 259 file.write(message)
260 file.flush()
261
UnsupportedOperation: not writable

So where does one start feeling the need for the paid product or get stumped without it?
what's missing in starting the server with code like this, v.s. the premium product? excluding security or enterprise integration features....

I'm running the above code using Spyder/Anaconda. When opening local host on port 8050, I only see a White window with "Loading..." on the top. Can anyone please help me?

datasource 'yahoo' works for me currently (Google does not)

I seem to be getting hung up at the decorator and the def update_graph. I get the * Running on http://127.0.0.1:8050/ (Press CTRL+C to quit) and then the program hangs.

Any ideas?

How about if i would like to use a dataset on that sample code?

How about if i would like to use a dataset on that sample code?