How to plot a vertical line at the x-axis range median position using plotly in Python API?

With the help of the @rpanai's answer and using plotly update buttons, the following solution is developed. Check this.

import pandas as pd
import plotly.graph_objs as go
from plotly.offline import init_notebook_mode, iplot

init_notebook_mode(connected=True)

df = pd.read_csv('https://raw.githubusercontent.com/yankev/test/master/life-expectancy-per-GDP-2007.csv')

americas = df[(df.continent=='Americas')]
europe = df[(df.continent=='Europe')]
# med_eur = europe["gdp_percap"].median()
# med_ame = americas["gdp_percap"].median()
# med_total=pd.DataFrame(list(europe["gdp_percap"])+list(americas["gdp_percap"])).median()[0]
med_eur = europe["gdp_percap"].max()/2
med_ame = americas["gdp_percap"].max()/2
med_total=25000

trace_median0 =  go.Scatter(x=[med_total, med_total],
                            y=[0,85],
                            mode="lines",
                            legendgroup="a",
                            showlegend=False,
                            marker=dict(size=12,
                                       line=dict(width=0.8),
                                       color="green"
                                       ),
                            name="Median Total"
                            )

trace_comp1 = go.Scatter(
    x=americas.gdp_percap,
    y=americas.life_exp,
    mode='markers',
    marker=dict(size=12,
                line=dict(width=1),
                color="navy"
               ),
    name='Americas',
    text=americas.country
    )

trace_median1 =  go.Scatter(x=[med_ame, med_ame],
                            y=[0,90],
                            mode="lines",
                            legendgroup="a",
                            showlegend=False,
                            marker=dict(size=12,
                                       line=dict(width=0.8),
                                       color="navy"
                                       ),
                            name="Median Americas",
                            visible=False
                            )
trace_comp2 = go.Scatter(
    x=europe.gdp_percap,
    y=europe.life_exp,
    mode='markers',
    marker=dict(size=12,
                line=dict(width=1),
                color="red"
               ),
    name='Europe',
    text=europe.country,
        )

trace_median2 =  go.Scatter(x=[med_eur, med_eur],
                            y=[0,90],
                            mode="lines",
                            legendgroup="b",
                            showlegend=False,
                            marker=dict(size=12,
                                       line=dict(width=0.8),
                                       color="red"
                                       ),
                            name="Median Europe",
                            visible=False
                            )

data_comp = [trace_comp1,trace_median1]+[trace_comp2,trace_median2]+[trace_median0]
layout_comp = go.Layout(
    title='Life Expectancy v. Per Capita GDP, 2007',
    hovermode='closest',
    xaxis=dict(
        title='GDP per capita (2000 dollars)',
        ticklen=5,
        zeroline=False,
        gridwidth=2,
        range=[0, 50_000],
    ),
    yaxis=dict(
        title='Life Expectancy (years)',
        ticklen=5,
        gridwidth=2,
        range=[0, 90],
    ),
    showlegend=False
)
updatemenus = list([
    dict(type="buttons",
         active=-1,
         buttons=list([
            dict(label = 'Total Dataset ',
                 method = 'update',
                 args = [{'visible': [True,False,True,False,True]},
                         {'title': 'Life Expectancy v. Per Capita GDP, 2007'}]),
            dict(label = 'Americas',
                 method = 'update',
                 args = [{'visible': [True,True, False, False,False]},
                         {'title': 'Americas'}]),
            dict(label = 'Europe',
                 method = 'update',
                 args = [{'visible': [False, False,True,True,False]},
                         {'title': 'Europe'}])
        ]),
    )
])

annotations = list([
    dict(text='Trace type:', x=0, y=1.085, yref='paper', align='left', showarrow=False)
])
layout_comp['updatemenus'] = updatemenus
layout_comp['annotations'] = annotations
fig_comp = go.Figure(data=data_comp, layout=layout_comp)
iplot(fig_comp)

You need to add so called callbacks to your program, so that the whole figure is updated when the database changes. Then you include a mean() to the definition of your x1 and x0 shape definitions. However this requires you to use dash.