spacex_dash_app.py

# Import required libraries
import pandas as pd
import dash
import dash_html_components as html
import dash_core_components as dcc
from dash.dependencies import Input, Output
import plotly.express as px

# Read the airline data into pandas dataframe
spacex_df = pd.read_csv("spacex_launch_dash.csv")
max_payload = spacex_df['Payload Mass (kg)'].max()
min_payload = spacex_df['Payload Mass (kg)'].min()

# Create a dash application
app = dash.Dash(__name__)

# Create an app layout
app.layout = html.Div(children=[
    html.H1('SpaceX First-Stage Landing Records Dashboard',
            style={'textAlign': 'center', 'color': '#503D36',
                    'font-size': 40}),

# TASK 1: Add a dropdown list to enable Launch Site selection
# The default select value is for ALL sites
    dcc.Dropdown(id='site-dropdown',
                options=[
                    {'label': 'All Sites', 'value': 'ALL'},
                    {'label': 'CCAFS LC-40', 'value': 'CCAFS LC-40'},
                    {'label': 'VAFB SLC-4E', 'value': 'VAFB SLC-4E'},
                    {'label': 'KSC LC-39A', 'value': 'KSC LC-39A'},
                    {'label': 'CCAFS SLC-40', 'value': 'CCAFS SLC-40'},                   
                ],
                value='ALL',
                placeholder="All Sites",
                searchable=True
                ),
    html.Br(),

# TASK 2: Add a pie chart to show the total successful launches count for all sites
# If a specific launch site was selected, show the Success vs. Failed counts for the site
    html.Div(dcc.Graph(id='success-pie-chart')),
    html.Br(),

    html.P("Payload range (Kg):"),
# TASK 3: Add a slider to select payload range
    dcc.RangeSlider(id='payload-slider',
                min=0, max=10000, step=1000,
                #marks={0: '0', 100: '100'},
                marks={i: str(i) for i in range(0, 10001, 1000)},
                value=[min_payload, max_payload]),

# TASK 4: Add a scatter chart to show the correlation between payload and launch success
    html.Div(dcc.Graph(id='success-payload-scatter-chart')),
    html.Br(),
])

# TASK 2:
# Add a callback function for `site-dropdown` as input, `success-pie-chart` as output
# Function decorator to specify function input and output
@app.callback(Output(component_id='success-pie-chart', component_property='figure'),
            [Input(component_id='site-dropdown', component_property='value')]) 

def get_pie_chart(entered_site):
    if entered_site == 'ALL':
        filtered_df = spacex_df.groupby('Launch Site')['class'].value_counts().reset_index(name='Count')
        fig = px.pie(filtered_df, values='Count', 
                     names='Launch Site', 
                     title='Total Success First-Stage Landings By Site')
        return fig
    else:
        filtered_df = spacex_df[spacex_df['Launch Site'] == entered_site]['class'].value_counts().reset_index(name='Count')
        filtered_df['Outcome'] = filtered_df['class'].map({1: 'Success', 0: 'Failure'})
        fig = px.pie(filtered_df, values='Count', 
                     names='Outcome', 
                     title=f'Success vs. Failed First-Stage Landings at {entered_site}')
        return fig

# TASK 4:
# Add a callback function for `site-dropdown` and `payload-slider` as inputs, `success-payload-scatter-chart` as output
@app.callback(Output(component_id='success-payload-scatter-chart', component_property='figure'),
            [Input(component_id='site-dropdown', component_property='value'), 
             Input(component_id="payload-slider", component_property="value")])

def update_scatter_chart(entered_site, payload_range):
    filtered_df = spacex_df
    
    if entered_site != 'ALL':
        filtered_df = filtered_df[filtered_df['Launch Site'] == entered_site]
    
    filtered_df = filtered_df[(filtered_df['Payload Mass (kg)'] >= payload_range[0]) & 
                              (filtered_df['Payload Mass (kg)'] <= payload_range[1])]
    
    fig = px.scatter(filtered_df, x='Payload Mass (kg)', y='class', color='Booster Version Category',
                     title='Correlation between Payload and Success for all Sites')
    
    return fig

# Run the app
if __name__ == '__main__':
    app.run_server()