histogram.py

@app.callback(
    Output("count_graph", "figure"),
    [
        Input("model_selector", "value"),
        Input("country_names", "value"),
        Input("year_selector", "value"),
    ],
)
def make_histogram(model, countries, years):

    cases = {}
    for year in years:
        for country in countries:
            for index, row in df[country].iterrows():
                if(row['week'][:4] == year):
                    if(row['date'] in cases):
                        cases[row['date']] += row['estimate_'+model]
                    else:
                        cases[row['date']] = row['estimate_'+model]
    
    weeks = []
    estimates = []
    for key in cases:
        weeks.append(datetime.strptime(key, '%Y-%m-%d'))
        estimates.append(cases[key])

    estimates = [x for _, x in sorted(zip(weeks, estimates))]
    weeks.sort()

    dff = {'week': weeks, 'cases': estimates}

    fig = px.bar(dff, x='week', y='cases',
                 hover_data=['cases'], color='cases',
                 labels={'cases': 'number of Influenza cases', 'week': 'Date'},
                 title='Cases over the years',)
    return fig