数据交互式可视化《Dash》框架学习（二）

Dash框架官方文档学习地址：https://dash.plot.ly/getting-started-part-2

一. Dash的基础调用

1.

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type='text'),
    html.Div(id='my-div')
])


@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input(component_id='my-id', component_property='value')]
)
def update_output_div(input_value):
    return 'You\'ve entered "{}"'.format(input_value)


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

2.

import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import plotly.graph_objs as go

df = pd.read_csv(
    'https://raw.githubusercontent.com/plotly/'
    'datasets/master/gapminderDataFiveYear.csv')

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    dcc.Graph(id='graph-with-slider'),
    dcc.Slider(
        id='year-slider',
        min=df['year'].min(),
        max=df['year'].max(),
        value=df['year'].min(),
        marks={str(year): str(year) for year in df['year'].unique()}
    )
])


@app.callback(
    dash.dependencies.Output('graph-with-slider', 'figure'),
    [dash.dependencies.Input('year-slider', 'value')])
def update_figure(selected_year):
    filtered_df = df[df.year == selected_year]
    traces = []
    for i in filtered_df.continent.unique():
        df_by_continent = filtered_df[filtered_df['continent'] == i]
        traces.append(go.Scatter(
            x=df_by_continent['gdpPercap'],
            y=df_by_continent['lifeExp'],
            text=df_by_continent['country'],
            mode='markers',
            opacity=0.7,
            marker={
                'size': 15,
                'line': {'width': 0.5, 'color': 'white'}
            },
            name=i
        ))

    return {
        'data': traces,
        'layout': go.Layout(
            xaxis={'type': 'log', 'title': 'GDP Per Capita'},
            yaxis={'title': 'Life Expectancy', 'range': [20, 90]},
            margin={'l': 40, 'b': 40, 't': 10, 'r': 10},
            legend={'x': 0, 'y': 1},
            hovermode='closest'
        )
    }


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

3. 多个输入

import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import plotly.graph_objs as go

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

df = pd.read_csv(
    'https://gist.githubusercontent.com/chriddyp/'
    'cb5392c35661370d95f300086accea51/raw/'
    '8e0768211f6b747c0db42a9ce9a0937dafcbd8b2/'
    'indicators.csv')

available_indicators = df['Indicator Name'].unique()

app.layout = html.Div([
    html.Div([

        html.Div([
            dcc.Dropdown(
                id='xaxis-column',
                options=[{'label': i, 'value': i} for i in available_indicators],
                value='Fertility rate, total (births per woman)'
            ),
            dcc.RadioItems(
                id='xaxis-type',
                options=[{'label': i, 'value': i} for i in ['Linear', 'Log']],
                value='Linear',
                labelStyle={'display': 'inline-block'}
            )
        ],
        style={'width': '48%', 'display': 'inline-block'}),

        html.Div([
            dcc.Dropdown(
                id='yaxis-column',
                options=[{'label': i, 'value': i} for i in available_indicators],
                value='Life expectancy at birth, total (years)'
            ),
            dcc.RadioItems(
                id='yaxis-type',
                options=[{'label': i, 'value': i} for i in ['Linear', 'Log']],
                value='Linear',
                labelStyle={'display': 'inline-block'}
            )
        ],style={'width': '48%', 'float': 'right', 'display': 'inline-block'})
    ]),

    dcc.Graph(id='indicator-graphic'),

    dcc.Slider(
        id='year--slider',
        min=df['Year'].min(),
        max=df['Year'].max(),
        value=df['Year'].max(),
        marks={str(year): str(year) for year in df['Year'].unique()}
    )
])

@app.callback(
    dash.dependencies.Output('indicator-graphic', 'figure'),
    [dash.dependencies.Input('xaxis-column', 'value'),
     dash.dependencies.Input('yaxis-column', 'value'),
     dash.dependencies.Input('xaxis-type', 'value'),
     dash.dependencies.Input('yaxis-type', 'value'),
     dash.dependencies.Input('year--slider', 'value')])
def update_graph(xaxis_column_name, yaxis_column_name,
                 xaxis_type, yaxis_type,
                 year_value):
    dff = df[df['Year'] == year_value]

    return {
        'data': [go.Scatter(
            x=dff[dff['Indicator Name'] == xaxis_column_name]['Value'],
            y=dff[dff['Indicator Name'] == yaxis_column_name]['Value'],
            text=dff[dff['Indicator Name'] == yaxis_column_name]['Country Name'],
            mode='markers',
            marker={
                'size': 15,
                'opacity': 0.5,
                'line': {'width': 0.5, 'color': 'white'}
            }
        )],
        'layout': go.Layout(
            xaxis={
                'title': xaxis_column_name,
                'type': 'linear' if xaxis_type == 'Linear' else 'log'
            },
            yaxis={
                'title': yaxis_column_name,
                'type': 'linear' if yaxis_type == 'Linear' else 'log'
            },
            margin={'l': 40, 'b': 40, 't': 10, 'r': 0},
            hovermode='closest'
        )
    }


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

4. 多个输出

import dash
import dash_core_components as dcc
import dash_html_components as html

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([
    dcc.RadioItems(
        id='dropdown-a',
        options=[{'label': i, 'value': i} for i in ['Canada', 'USA', 'Mexico']],
        value='Canada'
    ),
    html.Div(id='output-a'),

    dcc.RadioItems(
        id='dropdown-b',
        options=[{'label': i, 'value': i} for i in ['MTL', 'NYC', 'SF']],
        value='MTL'
    ),
    html.Div(id='output-b')

])


@app.callback(
    dash.dependencies.Output('output-a', 'children'),
    [dash.dependencies.Input('dropdown-a', 'value')])
def callback_a(dropdown_value):
    return 'You\'ve selected "{}"'.format(dropdown_value)


@app.callback(
    dash.dependencies.Output('output-b', 'children'),
    [dash.dependencies.Input('dropdown-b', 'value')])
def callback_b(dropdown_value):
    return 'You\'ve selected "{}"'.format(dropdown_value)


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

5. 两个有关联

# -*- coding: utf-8 -*-
import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

all_options = {
    'America': ['New York City', 'San Francisco', 'Cincinnati'],
    'Canada': [u'Montréal', 'Toronto', 'Ottawa']
}
app.layout = html.Div([
    dcc.RadioItems(
        id='countries-dropdown',
        options=[{'label': k, 'value': k} for k in all_options.keys()],
        value='America'
    ),

    html.Hr(),

    dcc.RadioItems(id='cities-dropdown'),

    html.Hr(),

    html.Div(id='display-selected-values')
])


@app.callback(
    dash.dependencies.Output('cities-dropdown', 'options'),
    [dash.dependencies.Input('countries-dropdown', 'value')])
def set_cities_options(selected_country):
    return [{'label': i, 'value': i} for i in all_options[selected_country]]


@app.callback(
    dash.dependencies.Output('cities-dropdown', 'value'),
    [dash.dependencies.Input('cities-dropdown', 'options')])
def set_cities_value(available_options):
    return available_options[0]['value']


@app.callback(
    dash.dependencies.Output('display-selected-values', 'children'),
    [dash.dependencies.Input('countries-dropdown', 'value'),
     dash.dependencies.Input('cities-dropdown', 'value')])
def set_display_children(selected_country, selected_city):
    return u'{} is a city in {}'.format(
        selected_city, selected_country,
    )


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

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