layout.py

callbacks.py

from datetime import datetime as dt

import pandas_datareader as pdr
from dash.dependencies import Input
from dash.dependencies import Output


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

layout.py

import dash_core_components as dcc
import dash_html_components as html

layout = html.Div([
    html.H1('Stock Tickers'),
    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'})