app.py

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output, State
import pandas_datareader.data as web
from os import environ
from datetime import datetime
import pandas as pd

environ['ALPHAVANTAGE_API_KEY'] = '' # Type API key here

app = dash.Dash()

nsdq = pd.read_csv('data/NASDAQcompanylist.csv')
nsdq.set_index('Symbol',inplace=True)
options = []

for tic in nsdq.index:
    options.append({'label': '{} {}'.format(tic, nsdq.loc[tic]['Name']), 'value': tic})

# Layout
app.layout = html.Div([
    html.H1('Stock Ticker Dashboard'),
    html.Div([
        html.H3('Enter a stock symbol: ', style={'paddingRight': '30px'}),
        dcc.Dropdown(
            id='my_stock_picker',
            options=options,
            value=['TSLA'],
            multi=True
        )
    ],
        style={'display': 'inline-block', 'verticalAlign': 'top','width':'30%'}
    ),
    html.Div([
        html.H3('Select a start and end date: '),
        dcc.DatePickerRange(
            id='my_date_picker',
            min_date_allowed=datetime(2010, 1, 1),
            max_date_allowed=datetime.today(),
            start_date=datetime(2020, 1, 1),
            end_date=datetime.today()
        )
    ],
        style={'display': 'inline-block'}
    ),
    html.Div([
        html.Button(
            id='submit_button',
            n_clicks=0,
            children='Submit',
            style={'fontSize': 24, 'marginLeft': '30px'}
        )
    ],
        style={'display':'inline-block'}
    ),
    dcc.Graph(
        id='my_graph',
        figure={
            'data': [
                {'x': [1, 2], 'y': [3, 1]}
            ]
        }
    )
])


@app.callback(
    Output('my_graph', 'figure'),
    [Input('submit_button','n_clicks')],
    [
        State('my_stock_picker', 'value'),
        State('my_date_picker', 'start_date'),
        State('my_date_picker', 'end_date')
    ]
)
def update_graph(n_clicks,stock_ticker, start_date, end_date):
    start = datetime.strptime(start_date[:10], '%Y-%m-%d')
    end = datetime.strptime(end_date[:10], '%Y-%m-%d')
    traces = []
    for tic in stock_ticker:
        df = web.DataReader(tic, 'av-daily', start, end)
        traces.append({'x': df.index, 'y': df['close'],'name':tic})

    fig = {
        'data':traces,
        'layout': {'title':', '.join(stock_ticker)+' Closing Prices'}
    }
    return fig


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