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Re-using Dash components

Your Dashboards are gaining traction, especially your recent date picker app. A senior manager loved it but requested some updates: use the corporately styled logo and display it in multiple places.

To keep your code clean, it's time to create a reusable Python function for the logo.

The approved logo style is: 'width':'75px', 'margin':'20px 20px 5px 5px', 'border':'1px dashed lightblue', 'display':'inline-block'

This exercise is part of the course

Building Dashboards with Dash and Plotly

View Course

Exercise instructions

  • Create a reusable component function called add_logo() below line 11 to return the corp_logo component.
  • Inside this function, create a Dash image element called corp_logo using the appropriate HTML component with the provided style below line 13.
  • Call the add_logo() function in each of the 4 marked spots below lines 20, 27, 30, and 46.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

from dash import Dash, dcc, html, Input, Output, callback
import plotly.express as px
import pandas as pd
from datetime import datetime, date
ecom_sales = pd.read_csv('/usr/local/share/datasets/ecom_sales.csv')
logo_link = 'https://assets.datacamp.com/production/repositories/5893/datasets/fdbe0accd2581a0c505dab4b29ebb66cf72a1803/e-comlogo.png'
ecom_sales['InvoiceDate'] = pd.to_datetime(ecom_sales['InvoiceDate'])

app = Dash()

# Create a reusable component function called add_logo
____ ____():
    # Create a Dash image element
    corp_logo = ____(
        src=logo_link, 
        style={'width':'75px', 'margin':'20px 20px 5px 5px', 'border':'1px dashed lightblue', 'display':'inline-block'})
    return corp_logo

app.layout = [
  # Insert the logo (1)
  ____,
  html.Br(),
  html.H1('Sales breakdowns'),
  html.Br(),
  html.Br(),
  html.Div([
        # Insert the logo (2)
        ____,
        html.H2('Controls', style={'margin':'0 10px','display':'inline-block'}),
        # Insert the logo (3)
        ____,
        html.H3('Sale Date Select'),
        html.Br(),
        dcc.DatePickerSingle(
            id='sale_date',
            min_date_allowed=ecom_sales.InvoiceDate.min(),
            max_date_allowed=ecom_sales.InvoiceDate.max(),
            initial_visible_month=date(2011, 4, 1),
            date=date(2011, 4, 11),
            style={'width':'200px', 'margin':'0 auto'})],   
        style={'width':'350px', 'height':'350px', 'display':'inline-block', 'vertical-align':'top', 'border':'1px solid black', 'padding':'20px'}),
  html.Div([
            dcc.Graph(id='sales_cat'),
            html.H2('Daily Sales by Major Category', style={'border':'2px solid black', 'width':'400px', 'margin':'0 auto'})],
            style={'width':'700px','display':'inline-block'}),
  # Insert the logo (4)
  ____
]
@callback(
    Output(component_id='sales_cat', component_property='figure'),
    Input(component_id='sale_date', component_property='date')
)
def update_plot(input_date):
    sales = ecom_sales.copy(deep=True)
    if input_date:
        sales = sales[sales['InvoiceDate'] == input_date]
    ecom_bar_major_cat = sales.groupby('Major Category')['OrderValue'].agg('sum').reset_index(name='Total Sales ($)')
    bar_fig_major_cat = px.bar(
        title=f'Sales on: {input_date}',data_frame=ecom_bar_major_cat, orientation='h', 
        x='Total Sales ($)', y='Major Category')
    return bar_fig_major_cat

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