DRY-styling Dash components
Your last dashboard benefited from reusable components. Now it's time to take it further: use a helper function to insert line breaks and simplify duplicated styling with a shared style function.
The common style elements you have noticed are: 'display':'inline-block','margin':'0 auto','padding':'20px'
The make_break()
function has been defined for you on line 14
, which takes an argument specifying how many HTML break tags to create and returns these in a list.
This exercise is part of the course
Building Dashboards with Dash and Plotly
Exercise instructions
- Create a function called
style_c()
that will return alayout_style
dictionary with all the common style elements ('display':'inline-block','margin':'0 auto','padding':'20px'
) below line21
. - Use the
make_break()
function to insert the number of line breaks marked in the comments below lines28
,31
, and29
. - Use the
style_c()
function to add styling to thehtml.H2()
component below line35
. - Use the
style_c()
function to add to the specific styling already on theDatePickerSingle()
component below line47
.
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()
def make_break(num_breaks):
br_list = [html.Br()] * num_breaks
return br_list
def add_logo():
corp_logo = html.Img(
src=logo_link,
style={'width':'75px','margin':'20px 20px 5px 5px','border':'1px dashed lightblue','display':'inline-block'})
return corp_logo
# Create a function to add corporate styling
def style_c():
layout_style = {____}
return layout_style
app.layout = [
add_logo(),
# Insert two HTML breaks
____,
html.H1('Sales breakdowns'),
# Insert three HTML breaks
____,
html.Div([
add_logo(),
# Style using the styling function
html.H2('Controls', style=____),
add_logo(),
html.H3('Sale Date Select'),
# Insert two HTML breaks
____,
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),
# Add styling using the styling function
style={'width':'200px'}.____(____))],
style={'width':'350px', 'height':'350px', 'vertical-align':'top', 'border':'1px solid black',
'display':'inline-block', 'margin':'0px 40px'}),
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'}),
add_logo()
]
@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)