Reactive calc

Exercise 2.2

Goal

Exercise

Extract reactive calculations from this app to reduce repetition and speed up the app. There are several good solutions to this problem, but the majority of people end up with two reactive calculations.

#| standalone: true
#| components: [viewer]
#| layout: horizontal
#| viewerHeight: 800
from shiny import App, render, ui, reactive
import pandas as pd
from pathlib import Path
from plots import dist_plot

infile = Path(__file__).parent / "penguins.csv"
penguins = pd.read_csv(infile)

app_ui = ui.page_fluid(
    ui.panel_title("Hello Penguins!"),
    ui.layout_sidebar(
        ui.panel_sidebar(
            ui.input_numeric("sample", "Sample Size", value=100),
            ui.input_slider(
                "mass",
                "Mass",
                2000,
                8000,
                6000,
            ),
            ui.input_selectize(
                "columns",
                "Columns",
                choices=penguins.columns.tolist(),
                selected=["species", "island"],
                multiple=True,
            ),
        ),
        ui.panel_main(
            ui.output_plot("mass_plot"),
            ui.output_text("row_count"),
            ui.output_data_frame("species_summary"),
        ),
    ),
)


def server(input, output, session):
    @reactive.Calc
    def sampled_df():
        return sample_data(penguins.copy(), input.sample())

    @reactive.Calc
    def filtered_df():
        df = sampled_df()
        return df.loc[df["body_mass"] < input.mass()]

    @render.plot
    def mass_plot():
        return dist_plot(sampled_df())

    @render.text
    def row_count():
        return f"{filtered_df().shape[0]} rows in filtered sample"

    @render.data_frame
    def species_summary():
        return filtered_df()[list(input.columns())]


app = App(app_ui, server)


def sample_data(data: pd.DataFrame, n: int) -> pd.DataFrame:
    # This loop is here to simulate a lengthy computation
    # pyodide does not support time.sleep() so this is the
    # workaround.
    for i in range(10000):
        out = data.sample(n, replace=True)
    return out

## file: penguins.csv
species,island,bill_length,bill_depth,flipper_length,body_mass,sex,year
Adelie,Torgersen,39.1,18.7,181,3750,male,2007
Adelie,Torgersen,39.5,17.4,186,3800,female,2007
Adelie,Torgersen,40.3,18,195,3250,female,2007
Adelie,Torgersen,NA,NA,NA,NA,NA,2007
Adelie,Torgersen,36.7,19.3,193,3450,female,2007
Adelie,Torgersen,39.3,20.6,190,3650,male,2007
Adelie,Torgersen,38.9,17.8,181,3625,female,2007
Adelie,Torgersen,39.2,19.6,195,4675,male,2007
Adelie,Torgersen,34.1,18.1,193,3475,NA,2007
Adelie,Torgersen,42,20.2,190,4250,NA,2007
Adelie,Torgersen,37.8,17.1,186,3300,NA,2007
Adelie,Torgersen,37.8,17.3,180,3700,NA,2007
Adelie,Torgersen,41.1,17.6,182,3200,female,2007
Adelie,Torgersen,38.6,21.2,191,3800,male,2007
Adelie,Torgersen,34.6,21.1,198,4400,male,2007
Adelie,Torgersen,36.6,17.8,185,3700,female,2007
Adelie,Torgersen,38.7,19,195,3450,female,2007
Adelie,Torgersen,42.5,20.7,197,4500,male,2007
Adelie,Torgersen,34.4,18.4,184,3325,female,2007
Adelie,Torgersen,46,21.5,194,4200,male,2007
Adelie,Biscoe,37.8,18.3,174,3400,female,2007
Adelie,Biscoe,37.7,18.7,180,3600,male,2007
Adelie,Biscoe,35.9,19.2,189,3800,female,2007
Adelie,Biscoe,38.2,18.1,185,3950,male,2007
Adelie,Biscoe,38.8,17.2,180,3800,male,2007
Adelie,Biscoe,35.3,18.9,187,3800,female,2007
Adelie,Biscoe,40.6,18.6,183,3550,male,2007
Adelie,Biscoe,40.5,17.9,187,3200,female,2007
Adelie,Biscoe,37.9,18.6,172,3150,female,2007
Adelie,Biscoe,40.5,18.9,180,3950,male,2007
Adelie,Dream,39.5,16.7,178,3250,female,2007
Adelie,Dream,37.2,18.1,178,3900,male,2007
Adelie,Dream,39.5,17.8,188,3300,female,2007
Adelie,Dream,40.9,18.9,184,3900,male,2007
Adelie,Dream,36.4,17,195,3325,female,2007
Adelie,Dream,39.2,21.1,196,4150,male,2007
Adelie,Dream,38.8,20,190,3950,male,2007
Adelie,Dream,42.2,18.5,180,3550,female,2007
Adelie,Dream,37.6,19.3,181,3300,female,2007
Adelie,Dream,39.8,19.1,184,4650,male,2007
Adelie,Dream,36.5,18,182,3150,female,2007
Adelie,Dream,40.8,18.4,195,3900,male,2007
Adelie,Dream,36,18.5,186,3100,female,2007
Adelie,Dream,44.1,19.7,196,4400,male,2007
Adelie,Dream,37,16.9,185,3000,female,2007
Adelie,Dream,39.6,18.8,190,4600,male,2007
Adelie,Dream,41.1,19,182,3425,male,2007
Adelie,Dream,37.5,18.9,179,2975,NA,2007
Adelie,Dream,36,17.9,190,3450,female,2007
Adelie,Dream,42.3,21.2,191,4150,male,2007
Adelie,Biscoe,39.6,17.7,186,3500,female,2008
Adelie,Biscoe,40.1,18.9,188,4300,male,2008
Adelie,Biscoe,35,17.9,190,3450,female,2008
Adelie,Biscoe,42,19.5,200,4050,male,2008
Adelie,Biscoe,34.5,18.1,187,2900,female,2008
Adelie,Biscoe,41.4,18.6,191,3700,male,2008
Adelie,Biscoe,39,17.5,186,3550,female,2008
Adelie,Biscoe,40.6,18.8,193,3800,male,2008
Adelie,Biscoe,36.5,16.6,181,2850,female,2008
Adelie,Biscoe,37.6,19.1,194,3750,male,2008
Adelie,Biscoe,35.7,16.9,185,3150,female,2008
Adelie,Biscoe,41.3,21.1,195,4400,male,2008
Adelie,Biscoe,37.6,17,185,3600,female,2008
Adelie,Biscoe,41.1,18.2,192,4050,male,2008
Adelie,Biscoe,36.4,17.1,184,2850,female,2008
Adelie,Biscoe,41.6,18,192,3950,male,2008
Adelie,Biscoe,35.5,16.2,195,3350,female,2008
Adelie,Biscoe,41.1,19.1,188,4100,male,2008
Adelie,Torgersen,35.9,16.6,190,3050,female,2008
Adelie,Torgersen,41.8,19.4,198,4450,male,2008
Adelie,Torgersen,33.5,19,190,3600,female,2008
Adelie,Torgersen,39.7,18.4,190,3900,male,2008
Adelie,Torgersen,39.6,17.2,196,3550,female,2008
Adelie,Torgersen,45.8,18.9,197,4150,male,2008
Adelie,Torgersen,35.5,17.5,190,3700,female,2008
Adelie,Torgersen,42.8,18.5,195,4250,male,2008
Adelie,Torgersen,40.9,16.8,191,3700,female,2008
Adelie,Torgersen,37.2,19.4,184,3900,male,2008
Adelie,Torgersen,36.2,16.1,187,3550,female,2008
Adelie,Torgersen,42.1,19.1,195,4000,male,2008
Adelie,Torgersen,34.6,17.2,189,3200,female,2008
Adelie,Torgersen,42.9,17.6,196,4700,male,2008
Adelie,Torgersen,36.7,18.8,187,3800,female,2008
Adelie,Torgersen,35.1,19.4,193,4200,male,2008
Adelie,Dream,37.3,17.8,191,3350,female,2008
Adelie,Dream,41.3,20.3,194,3550,male,2008
Adelie,Dream,36.3,19.5,190,3800,male,2008
Adelie,Dream,36.9,18.6,189,3500,female,2008
Adelie,Dream,38.3,19.2,189,3950,male,2008
Adelie,Dream,38.9,18.8,190,3600,female,2008
Adelie,Dream,35.7,18,202,3550,female,2008
Adelie,Dream,41.1,18.1,205,4300,male,2008
Adelie,Dream,34,17.1,185,3400,female,2008
Adelie,Dream,39.6,18.1,186,4450,male,2008
Adelie,Dream,36.2,17.3,187,3300,female,2008
Adelie,Dream,40.8,18.9,208,4300,male,2008
Adelie,Dream,38.1,18.6,190,3700,female,2008
Adelie,Dream,40.3,18.5,196,4350,male,2008
Adelie,Dream,33.1,16.1,178,2900,female,2008
Adelie,Dream,43.2,18.5,192,4100,male,2008
Adelie,Biscoe,35,17.9,192,3725,female,2009
Adelie,Biscoe,41,20,203,4725,male,2009
Adelie,Biscoe,37.7,16,183,3075,female,2009
Adelie,Biscoe,37.8,20,190,4250,male,2009
Adelie,Biscoe,37.9,18.6,193,2925,female,2009
Adelie,Biscoe,39.7,18.9,184,3550,male,2009
Adelie,Biscoe,38.6,17.2,199,3750,female,2009
Adelie,Biscoe,38.2,20,190,3900,male,2009
Adelie,Biscoe,38.1,17,181,3175,female,2009
Adelie,Biscoe,43.2,19,197,4775,male,2009
Adelie,Biscoe,38.1,16.5,198,3825,female,2009
Adelie,Biscoe,45.6,20.3,191,4600,male,2009
Adelie,Biscoe,39.7,17.7,193,3200,female,2009
Adelie,Biscoe,42.2,19.5,197,4275,male,2009
Adelie,Biscoe,39.6,20.7,191,3900,female,2009
Adelie,Biscoe,42.7,18.3,196,4075,male,2009
Adelie,Torgersen,38.6,17,188,2900,female,2009
Adelie,Torgersen,37.3,20.5,199,3775,male,2009
Adelie,Torgersen,35.7,17,189,3350,female,2009
Adelie,Torgersen,41.1,18.6,189,3325,male,2009
Adelie,Torgersen,36.2,17.2,187,3150,female,2009
Adelie,Torgersen,37.7,19.8,198,3500,male,2009
Adelie,Torgersen,40.2,17,176,3450,female,2009
Adelie,Torgersen,41.4,18.5,202,3875,male,2009
Adelie,Torgersen,35.2,15.9,186,3050,female,2009
Adelie,Torgersen,40.6,19,199,4000,male,2009
Adelie,Torgersen,38.8,17.6,191,3275,female,2009
Adelie,Torgersen,41.5,18.3,195,4300,male,2009
Adelie,Torgersen,39,17.1,191,3050,female,2009
Adelie,Torgersen,44.1,18,210,4000,male,2009
Adelie,Torgersen,38.5,17.9,190,3325,female,2009
Adelie,Torgersen,43.1,19.2,197,3500,male,2009
Adelie,Dream,36.8,18.5,193,3500,female,2009
Adelie,Dream,37.5,18.5,199,4475,male,2009
Adelie,Dream,38.1,17.6,187,3425,female,2009
Adelie,Dream,41.1,17.5,190,3900,male,2009
Adelie,Dream,35.6,17.5,191,3175,female,2009
Adelie,Dream,40.2,20.1,200,3975,male,2009
Adelie,Dream,37,16.5,185,3400,female,2009
Adelie,Dream,39.7,17.9,193,4250,male,2009
Adelie,Dream,40.2,17.1,193,3400,female,2009
Adelie,Dream,40.6,17.2,187,3475,male,2009
Adelie,Dream,32.1,15.5,188,3050,female,2009
Adelie,Dream,40.7,17,190,3725,male,2009
Adelie,Dream,37.3,16.8,192,3000,female,2009
Adelie,Dream,39,18.7,185,3650,male,2009
Adelie,Dream,39.2,18.6,190,4250,male,2009
Adelie,Dream,36.6,18.4,184,3475,female,2009
Adelie,Dream,36,17.8,195,3450,female,2009
Adelie,Dream,37.8,18.1,193,3750,male,2009
Adelie,Dream,36,17.1,187,3700,female,2009
Adelie,Dream,41.5,18.5,201,4000,male,2009
Gentoo,Biscoe,46.1,13.2,211,4500,female,2007
Gentoo,Biscoe,50,16.3,230,5700,male,2007
Gentoo,Biscoe,48.7,14.1,210,4450,female,2007
Gentoo,Biscoe,50,15.2,218,5700,male,2007
Gentoo,Biscoe,47.6,14.5,215,5400,male,2007
Gentoo,Biscoe,46.5,13.5,210,4550,female,2007
Gentoo,Biscoe,45.4,14.6,211,4800,female,2007
Gentoo,Biscoe,46.7,15.3,219,5200,male,2007
Gentoo,Biscoe,43.3,13.4,209,4400,female,2007
Gentoo,Biscoe,46.8,15.4,215,5150,male,2007
Gentoo,Biscoe,40.9,13.7,214,4650,female,2007
Gentoo,Biscoe,49,16.1,216,5550,male,2007
Gentoo,Biscoe,45.5,13.7,214,4650,female,2007
Gentoo,Biscoe,48.4,14.6,213,5850,male,2007
Gentoo,Biscoe,45.8,14.6,210,4200,female,2007
Gentoo,Biscoe,49.3,15.7,217,5850,male,2007
Gentoo,Biscoe,42,13.5,210,4150,female,2007
Gentoo,Biscoe,49.2,15.2,221,6300,male,2007
Gentoo,Biscoe,46.2,14.5,209,4800,female,2007
Gentoo,Biscoe,48.7,15.1,222,5350,male,2007
Gentoo,Biscoe,50.2,14.3,218,5700,male,2007
Gentoo,Biscoe,45.1,14.5,215,5000,female,2007
Gentoo,Biscoe,46.5,14.5,213,4400,female,2007
Gentoo,Biscoe,46.3,15.8,215,5050,male,2007
Gentoo,Biscoe,42.9,13.1,215,5000,female,2007
Gentoo,Biscoe,46.1,15.1,215,5100,male,2007
Gentoo,Biscoe,44.5,14.3,216,4100,NA,2007
Gentoo,Biscoe,47.8,15,215,5650,male,2007
Gentoo,Biscoe,48.2,14.3,210,4600,female,2007
Gentoo,Biscoe,50,15.3,220,5550,male,2007
Gentoo,Biscoe,47.3,15.3,222,5250,male,2007
Gentoo,Biscoe,42.8,14.2,209,4700,female,2007
Gentoo,Biscoe,45.1,14.5,207,5050,female,2007
Gentoo,Biscoe,59.6,17,230,6050,male,2007
Gentoo,Biscoe,49.1,14.8,220,5150,female,2008
Gentoo,Biscoe,48.4,16.3,220,5400,male,2008
Gentoo,Biscoe,42.6,13.7,213,4950,female,2008
Gentoo,Biscoe,44.4,17.3,219,5250,male,2008
Gentoo,Biscoe,44,13.6,208,4350,female,2008
Gentoo,Biscoe,48.7,15.7,208,5350,male,2008
Gentoo,Biscoe,42.7,13.7,208,3950,female,2008
Gentoo,Biscoe,49.6,16,225,5700,male,2008
Gentoo,Biscoe,45.3,13.7,210,4300,female,2008
Gentoo,Biscoe,49.6,15,216,4750,male,2008
Gentoo,Biscoe,50.5,15.9,222,5550,male,2008
Gentoo,Biscoe,43.6,13.9,217,4900,female,2008
Gentoo,Biscoe,45.5,13.9,210,4200,female,2008
Gentoo,Biscoe,50.5,15.9,225,5400,male,2008
Gentoo,Biscoe,44.9,13.3,213,5100,female,2008
Gentoo,Biscoe,45.2,15.8,215,5300,male,2008
Gentoo,Biscoe,46.6,14.2,210,4850,female,2008
Gentoo,Biscoe,48.5,14.1,220,5300,male,2008
Gentoo,Biscoe,45.1,14.4,210,4400,female,2008
Gentoo,Biscoe,50.1,15,225,5000,male,2008
Gentoo,Biscoe,46.5,14.4,217,4900,female,2008
Gentoo,Biscoe,45,15.4,220,5050,male,2008
Gentoo,Biscoe,43.8,13.9,208,4300,female,2008
Gentoo,Biscoe,45.5,15,220,5000,male,2008
Gentoo,Biscoe,43.2,14.5,208,4450,female,2008
Gentoo,Biscoe,50.4,15.3,224,5550,male,2008
Gentoo,Biscoe,45.3,13.8,208,4200,female,2008
Gentoo,Biscoe,46.2,14.9,221,5300,male,2008
Gentoo,Biscoe,45.7,13.9,214,4400,female,2008
Gentoo,Biscoe,54.3,15.7,231,5650,male,2008
Gentoo,Biscoe,45.8,14.2,219,4700,female,2008
Gentoo,Biscoe,49.8,16.8,230,5700,male,2008
Gentoo,Biscoe,46.2,14.4,214,4650,NA,2008
Gentoo,Biscoe,49.5,16.2,229,5800,male,2008
Gentoo,Biscoe,43.5,14.2,220,4700,female,2008
Gentoo,Biscoe,50.7,15,223,5550,male,2008
Gentoo,Biscoe,47.7,15,216,4750,female,2008
Gentoo,Biscoe,46.4,15.6,221,5000,male,2008
Gentoo,Biscoe,48.2,15.6,221,5100,male,2008
Gentoo,Biscoe,46.5,14.8,217,5200,female,2008
Gentoo,Biscoe,46.4,15,216,4700,female,2008
Gentoo,Biscoe,48.6,16,230,5800,male,2008
Gentoo,Biscoe,47.5,14.2,209,4600,female,2008
Gentoo,Biscoe,51.1,16.3,220,6000,male,2008
Gentoo,Biscoe,45.2,13.8,215,4750,female,2008
Gentoo,Biscoe,45.2,16.4,223,5950,male,2008
Gentoo,Biscoe,49.1,14.5,212,4625,female,2009
Gentoo,Biscoe,52.5,15.6,221,5450,male,2009
Gentoo,Biscoe,47.4,14.6,212,4725,female,2009
Gentoo,Biscoe,50,15.9,224,5350,male,2009
Gentoo,Biscoe,44.9,13.8,212,4750,female,2009
Gentoo,Biscoe,50.8,17.3,228,5600,male,2009
Gentoo,Biscoe,43.4,14.4,218,4600,female,2009
Gentoo,Biscoe,51.3,14.2,218,5300,male,2009
Gentoo,Biscoe,47.5,14,212,4875,female,2009
Gentoo,Biscoe,52.1,17,230,5550,male,2009
Gentoo,Biscoe,47.5,15,218,4950,female,2009
Gentoo,Biscoe,52.2,17.1,228,5400,male,2009
Gentoo,Biscoe,45.5,14.5,212,4750,female,2009
Gentoo,Biscoe,49.5,16.1,224,5650,male,2009
Gentoo,Biscoe,44.5,14.7,214,4850,female,2009
Gentoo,Biscoe,50.8,15.7,226,5200,male,2009
Gentoo,Biscoe,49.4,15.8,216,4925,male,2009
Gentoo,Biscoe,46.9,14.6,222,4875,female,2009
Gentoo,Biscoe,48.4,14.4,203,4625,female,2009
Gentoo,Biscoe,51.1,16.5,225,5250,male,2009
Gentoo,Biscoe,48.5,15,219,4850,female,2009
Gentoo,Biscoe,55.9,17,228,5600,male,2009
Gentoo,Biscoe,47.2,15.5,215,4975,female,2009
Gentoo,Biscoe,49.1,15,228,5500,male,2009
Gentoo,Biscoe,47.3,13.8,216,4725,NA,2009
Gentoo,Biscoe,46.8,16.1,215,5500,male,2009
Gentoo,Biscoe,41.7,14.7,210,4700,female,2009
Gentoo,Biscoe,53.4,15.8,219,5500,male,2009
Gentoo,Biscoe,43.3,14,208,4575,female,2009
Gentoo,Biscoe,48.1,15.1,209,5500,male,2009
Gentoo,Biscoe,50.5,15.2,216,5000,female,2009
Gentoo,Biscoe,49.8,15.9,229,5950,male,2009
Gentoo,Biscoe,43.5,15.2,213,4650,female,2009
Gentoo,Biscoe,51.5,16.3,230,5500,male,2009
Gentoo,Biscoe,46.2,14.1,217,4375,female,2009
Gentoo,Biscoe,55.1,16,230,5850,male,2009
Gentoo,Biscoe,44.5,15.7,217,4875,NA,2009
Gentoo,Biscoe,48.8,16.2,222,6000,male,2009
Gentoo,Biscoe,47.2,13.7,214,4925,female,2009
Gentoo,Biscoe,NA,NA,NA,NA,NA,2009
Gentoo,Biscoe,46.8,14.3,215,4850,female,2009
Gentoo,Biscoe,50.4,15.7,222,5750,male,2009
Gentoo,Biscoe,45.2,14.8,212,5200,female,2009
Gentoo,Biscoe,49.9,16.1,213,5400,male,2009
Chinstrap,Dream,46.5,17.9,192,3500,female,2007
Chinstrap,Dream,50,19.5,196,3900,male,2007
Chinstrap,Dream,51.3,19.2,193,3650,male,2007
Chinstrap,Dream,45.4,18.7,188,3525,female,2007
Chinstrap,Dream,52.7,19.8,197,3725,male,2007
Chinstrap,Dream,45.2,17.8,198,3950,female,2007
Chinstrap,Dream,46.1,18.2,178,3250,female,2007
Chinstrap,Dream,51.3,18.2,197,3750,male,2007
Chinstrap,Dream,46,18.9,195,4150,female,2007
Chinstrap,Dream,51.3,19.9,198,3700,male,2007
Chinstrap,Dream,46.6,17.8,193,3800,female,2007
Chinstrap,Dream,51.7,20.3,194,3775,male,2007
Chinstrap,Dream,47,17.3,185,3700,female,2007
Chinstrap,Dream,52,18.1,201,4050,male,2007
Chinstrap,Dream,45.9,17.1,190,3575,female,2007
Chinstrap,Dream,50.5,19.6,201,4050,male,2007
Chinstrap,Dream,50.3,20,197,3300,male,2007
Chinstrap,Dream,58,17.8,181,3700,female,2007
Chinstrap,Dream,46.4,18.6,190,3450,female,2007
Chinstrap,Dream,49.2,18.2,195,4400,male,2007
Chinstrap,Dream,42.4,17.3,181,3600,female,2007
Chinstrap,Dream,48.5,17.5,191,3400,male,2007
Chinstrap,Dream,43.2,16.6,187,2900,female,2007
Chinstrap,Dream,50.6,19.4,193,3800,male,2007
Chinstrap,Dream,46.7,17.9,195,3300,female,2007
Chinstrap,Dream,52,19,197,4150,male,2007
Chinstrap,Dream,50.5,18.4,200,3400,female,2008
Chinstrap,Dream,49.5,19,200,3800,male,2008
Chinstrap,Dream,46.4,17.8,191,3700,female,2008
Chinstrap,Dream,52.8,20,205,4550,male,2008
Chinstrap,Dream,40.9,16.6,187,3200,female,2008
Chinstrap,Dream,54.2,20.8,201,4300,male,2008
Chinstrap,Dream,42.5,16.7,187,3350,female,2008
Chinstrap,Dream,51,18.8,203,4100,male,2008
Chinstrap,Dream,49.7,18.6,195,3600,male,2008
Chinstrap,Dream,47.5,16.8,199,3900,female,2008
Chinstrap,Dream,47.6,18.3,195,3850,female,2008
Chinstrap,Dream,52,20.7,210,4800,male,2008
Chinstrap,Dream,46.9,16.6,192,2700,female,2008
Chinstrap,Dream,53.5,19.9,205,4500,male,2008
Chinstrap,Dream,49,19.5,210,3950,male,2008
Chinstrap,Dream,46.2,17.5,187,3650,female,2008
Chinstrap,Dream,50.9,19.1,196,3550,male,2008
Chinstrap,Dream,45.5,17,196,3500,female,2008
Chinstrap,Dream,50.9,17.9,196,3675,female,2009
Chinstrap,Dream,50.8,18.5,201,4450,male,2009
Chinstrap,Dream,50.1,17.9,190,3400,female,2009
Chinstrap,Dream,49,19.6,212,4300,male,2009
Chinstrap,Dream,51.5,18.7,187,3250,male,2009
Chinstrap,Dream,49.8,17.3,198,3675,female,2009
Chinstrap,Dream,48.1,16.4,199,3325,female,2009
Chinstrap,Dream,51.4,19,201,3950,male,2009
Chinstrap,Dream,45.7,17.3,193,3600,female,2009
Chinstrap,Dream,50.7,19.7,203,4050,male,2009
Chinstrap,Dream,42.5,17.3,187,3350,female,2009
Chinstrap,Dream,52.2,18.8,197,3450,male,2009
Chinstrap,Dream,45.2,16.6,191,3250,female,2009
Chinstrap,Dream,49.3,19.9,203,4050,male,2009
Chinstrap,Dream,50.2,18.8,202,3800,male,2009
Chinstrap,Dream,45.6,19.4,194,3525,female,2009
Chinstrap,Dream,51.9,19.5,206,3950,male,2009
Chinstrap,Dream,46.8,16.5,189,3650,female,2009
Chinstrap,Dream,45.7,17,195,3650,female,2009
Chinstrap,Dream,55.8,19.8,207,4000,male,2009
Chinstrap,Dream,43.5,18.1,202,3400,female,2009
Chinstrap,Dream,49.6,18.2,193,3775,male,2009
Chinstrap,Dream,50.8,19,210,4100,male,2009
Chinstrap,Dream,50.2,18.7,198,3775,female,2009

## file: plots.py
from plotnine import ggplot, geom_density, aes, theme_light, geom_point, stat_smooth


def dist_plot(df):
    plot = (
        ggplot(df, aes(x="body_mass", fill="species"))
        + geom_density(alpha=0.2)
        + theme_light()
    )
    return plot


def scatter_plot(df, trend_line=False):
    plot = (
        ggplot(
            df,
            aes(
                x="bill_length",
                y="bill_depth",
                color="species",
                group="species",
            ),
        )
        + geom_point()
        + theme_light()
    )

    if trend_line:
        plot = plot + stat_smooth()

    return plot

Problem

Exercise

Extract reactive calculations from this app to reduce repetition and speed up the app. There are several good solutions to this problem, but the majority of people end up with two reactive calculations.

#| standalone: true
#| components: [editor, viewer]
#| layout: horizontal
#| viewerHeight: 800
from shiny import App, render, ui, reactive
import pandas as pd
from pathlib import Path
from plots import dist_plot

infile = Path(__file__).parent / "penguins.csv"
penguins = pd.read_csv(infile)

app_ui = ui.page_fluid(
    ui.panel_title("Hello Penguins!"),
    ui.layout_sidebar(
        ui.panel_sidebar(
            ui.input_numeric("sample", "Sample Size", value=100),
            ui.input_slider(
                "mass",
                "Mass",
                2000,
                8000,
                6000,
            ),
            ui.input_selectize(
                "columns",
                "Columns",
                choices=penguins.columns.tolist(),
                selected=["species", "island"],
                multiple=True,
            ),
        ),
        ui.panel_main(
            ui.output_plot("mass_plot"),
            ui.output_text("row_count"),
            ui.output_data_frame("species_summary"),
        ),
    ),
)


def server(input, output, session):
    @render.plot
    def mass_plot():
        df = sample_data(penguins.copy(), input.sample())
        return dist_plot(df)

    @render.text
    def row_count():
        df = sample_data(penguins.copy(), input.sample())
        df = df.loc[df["body_mass"] < input.mass()]
        return f"{df.shape[0]} rows in filtered sample"

    @render.data_frame
    def species_summary():
        df = sample_data(penguins.copy(), input.sample())
        filtered = df.loc[df["body_mass"] < input.mass()]
        return filtered[list(input.columns())]


app = App(app_ui, server)


def sample_data(data: pd.DataFrame, n: int) -> pd.DataFrame:
    # This loop is here to simulate a lengthy computation
    # pyodide does not support time.sleep() so this is the
    # workaround.
    for i in range(10000):
        out = data.sample(n, replace=True)
    return out

## file: penguins.csv
species,island,bill_length,bill_depth,flipper_length,body_mass,sex,year
Adelie,Torgersen,39.1,18.7,181,3750,male,2007
Adelie,Torgersen,39.5,17.4,186,3800,female,2007
Adelie,Torgersen,40.3,18,195,3250,female,2007
Adelie,Torgersen,NA,NA,NA,NA,NA,2007
Adelie,Torgersen,36.7,19.3,193,3450,female,2007
Adelie,Torgersen,39.3,20.6,190,3650,male,2007
Adelie,Torgersen,38.9,17.8,181,3625,female,2007
Adelie,Torgersen,39.2,19.6,195,4675,male,2007
Adelie,Torgersen,34.1,18.1,193,3475,NA,2007
Adelie,Torgersen,42,20.2,190,4250,NA,2007
Adelie,Torgersen,37.8,17.1,186,3300,NA,2007
Adelie,Torgersen,37.8,17.3,180,3700,NA,2007
Adelie,Torgersen,41.1,17.6,182,3200,female,2007
Adelie,Torgersen,38.6,21.2,191,3800,male,2007
Adelie,Torgersen,34.6,21.1,198,4400,male,2007
Adelie,Torgersen,36.6,17.8,185,3700,female,2007
Adelie,Torgersen,38.7,19,195,3450,female,2007
Adelie,Torgersen,42.5,20.7,197,4500,male,2007
Adelie,Torgersen,34.4,18.4,184,3325,female,2007
Adelie,Torgersen,46,21.5,194,4200,male,2007
Adelie,Biscoe,37.8,18.3,174,3400,female,2007
Adelie,Biscoe,37.7,18.7,180,3600,male,2007
Adelie,Biscoe,35.9,19.2,189,3800,female,2007
Adelie,Biscoe,38.2,18.1,185,3950,male,2007
Adelie,Biscoe,38.8,17.2,180,3800,male,2007
Adelie,Biscoe,35.3,18.9,187,3800,female,2007
Adelie,Biscoe,40.6,18.6,183,3550,male,2007
Adelie,Biscoe,40.5,17.9,187,3200,female,2007
Adelie,Biscoe,37.9,18.6,172,3150,female,2007
Adelie,Biscoe,40.5,18.9,180,3950,male,2007
Adelie,Dream,39.5,16.7,178,3250,female,2007
Adelie,Dream,37.2,18.1,178,3900,male,2007
Adelie,Dream,39.5,17.8,188,3300,female,2007
Adelie,Dream,40.9,18.9,184,3900,male,2007
Adelie,Dream,36.4,17,195,3325,female,2007
Adelie,Dream,39.2,21.1,196,4150,male,2007
Adelie,Dream,38.8,20,190,3950,male,2007
Adelie,Dream,42.2,18.5,180,3550,female,2007
Adelie,Dream,37.6,19.3,181,3300,female,2007
Adelie,Dream,39.8,19.1,184,4650,male,2007
Adelie,Dream,36.5,18,182,3150,female,2007
Adelie,Dream,40.8,18.4,195,3900,male,2007
Adelie,Dream,36,18.5,186,3100,female,2007
Adelie,Dream,44.1,19.7,196,4400,male,2007
Adelie,Dream,37,16.9,185,3000,female,2007
Adelie,Dream,39.6,18.8,190,4600,male,2007
Adelie,Dream,41.1,19,182,3425,male,2007
Adelie,Dream,37.5,18.9,179,2975,NA,2007
Adelie,Dream,36,17.9,190,3450,female,2007
Adelie,Dream,42.3,21.2,191,4150,male,2007
Adelie,Biscoe,39.6,17.7,186,3500,female,2008
Adelie,Biscoe,40.1,18.9,188,4300,male,2008
Adelie,Biscoe,35,17.9,190,3450,female,2008
Adelie,Biscoe,42,19.5,200,4050,male,2008
Adelie,Biscoe,34.5,18.1,187,2900,female,2008
Adelie,Biscoe,41.4,18.6,191,3700,male,2008
Adelie,Biscoe,39,17.5,186,3550,female,2008
Adelie,Biscoe,40.6,18.8,193,3800,male,2008
Adelie,Biscoe,36.5,16.6,181,2850,female,2008
Adelie,Biscoe,37.6,19.1,194,3750,male,2008
Adelie,Biscoe,35.7,16.9,185,3150,female,2008
Adelie,Biscoe,41.3,21.1,195,4400,male,2008
Adelie,Biscoe,37.6,17,185,3600,female,2008
Adelie,Biscoe,41.1,18.2,192,4050,male,2008
Adelie,Biscoe,36.4,17.1,184,2850,female,2008
Adelie,Biscoe,41.6,18,192,3950,male,2008
Adelie,Biscoe,35.5,16.2,195,3350,female,2008
Adelie,Biscoe,41.1,19.1,188,4100,male,2008
Adelie,Torgersen,35.9,16.6,190,3050,female,2008
Adelie,Torgersen,41.8,19.4,198,4450,male,2008
Adelie,Torgersen,33.5,19,190,3600,female,2008
Adelie,Torgersen,39.7,18.4,190,3900,male,2008
Adelie,Torgersen,39.6,17.2,196,3550,female,2008
Adelie,Torgersen,45.8,18.9,197,4150,male,2008
Adelie,Torgersen,35.5,17.5,190,3700,female,2008
Adelie,Torgersen,42.8,18.5,195,4250,male,2008
Adelie,Torgersen,40.9,16.8,191,3700,female,2008
Adelie,Torgersen,37.2,19.4,184,3900,male,2008
Adelie,Torgersen,36.2,16.1,187,3550,female,2008
Adelie,Torgersen,42.1,19.1,195,4000,male,2008
Adelie,Torgersen,34.6,17.2,189,3200,female,2008
Adelie,Torgersen,42.9,17.6,196,4700,male,2008
Adelie,Torgersen,36.7,18.8,187,3800,female,2008
Adelie,Torgersen,35.1,19.4,193,4200,male,2008
Adelie,Dream,37.3,17.8,191,3350,female,2008
Adelie,Dream,41.3,20.3,194,3550,male,2008
Adelie,Dream,36.3,19.5,190,3800,male,2008
Adelie,Dream,36.9,18.6,189,3500,female,2008
Adelie,Dream,38.3,19.2,189,3950,male,2008
Adelie,Dream,38.9,18.8,190,3600,female,2008
Adelie,Dream,35.7,18,202,3550,female,2008
Adelie,Dream,41.1,18.1,205,4300,male,2008
Adelie,Dream,34,17.1,185,3400,female,2008
Adelie,Dream,39.6,18.1,186,4450,male,2008
Adelie,Dream,36.2,17.3,187,3300,female,2008
Adelie,Dream,40.8,18.9,208,4300,male,2008
Adelie,Dream,38.1,18.6,190,3700,female,2008
Adelie,Dream,40.3,18.5,196,4350,male,2008
Adelie,Dream,33.1,16.1,178,2900,female,2008
Adelie,Dream,43.2,18.5,192,4100,male,2008
Adelie,Biscoe,35,17.9,192,3725,female,2009
Adelie,Biscoe,41,20,203,4725,male,2009
Adelie,Biscoe,37.7,16,183,3075,female,2009
Adelie,Biscoe,37.8,20,190,4250,male,2009
Adelie,Biscoe,37.9,18.6,193,2925,female,2009
Adelie,Biscoe,39.7,18.9,184,3550,male,2009
Adelie,Biscoe,38.6,17.2,199,3750,female,2009
Adelie,Biscoe,38.2,20,190,3900,male,2009
Adelie,Biscoe,38.1,17,181,3175,female,2009
Adelie,Biscoe,43.2,19,197,4775,male,2009
Adelie,Biscoe,38.1,16.5,198,3825,female,2009
Adelie,Biscoe,45.6,20.3,191,4600,male,2009
Adelie,Biscoe,39.7,17.7,193,3200,female,2009
Adelie,Biscoe,42.2,19.5,197,4275,male,2009
Adelie,Biscoe,39.6,20.7,191,3900,female,2009
Adelie,Biscoe,42.7,18.3,196,4075,male,2009
Adelie,Torgersen,38.6,17,188,2900,female,2009
Adelie,Torgersen,37.3,20.5,199,3775,male,2009
Adelie,Torgersen,35.7,17,189,3350,female,2009
Adelie,Torgersen,41.1,18.6,189,3325,male,2009
Adelie,Torgersen,36.2,17.2,187,3150,female,2009
Adelie,Torgersen,37.7,19.8,198,3500,male,2009
Adelie,Torgersen,40.2,17,176,3450,female,2009
Adelie,Torgersen,41.4,18.5,202,3875,male,2009
Adelie,Torgersen,35.2,15.9,186,3050,female,2009
Adelie,Torgersen,40.6,19,199,4000,male,2009
Adelie,Torgersen,38.8,17.6,191,3275,female,2009
Adelie,Torgersen,41.5,18.3,195,4300,male,2009
Adelie,Torgersen,39,17.1,191,3050,female,2009
Adelie,Torgersen,44.1,18,210,4000,male,2009
Adelie,Torgersen,38.5,17.9,190,3325,female,2009
Adelie,Torgersen,43.1,19.2,197,3500,male,2009
Adelie,Dream,36.8,18.5,193,3500,female,2009
Adelie,Dream,37.5,18.5,199,4475,male,2009
Adelie,Dream,38.1,17.6,187,3425,female,2009
Adelie,Dream,41.1,17.5,190,3900,male,2009
Adelie,Dream,35.6,17.5,191,3175,female,2009
Adelie,Dream,40.2,20.1,200,3975,male,2009
Adelie,Dream,37,16.5,185,3400,female,2009
Adelie,Dream,39.7,17.9,193,4250,male,2009
Adelie,Dream,40.2,17.1,193,3400,female,2009
Adelie,Dream,40.6,17.2,187,3475,male,2009
Adelie,Dream,32.1,15.5,188,3050,female,2009
Adelie,Dream,40.7,17,190,3725,male,2009
Adelie,Dream,37.3,16.8,192,3000,female,2009
Adelie,Dream,39,18.7,185,3650,male,2009
Adelie,Dream,39.2,18.6,190,4250,male,2009
Adelie,Dream,36.6,18.4,184,3475,female,2009
Adelie,Dream,36,17.8,195,3450,female,2009
Adelie,Dream,37.8,18.1,193,3750,male,2009
Adelie,Dream,36,17.1,187,3700,female,2009
Adelie,Dream,41.5,18.5,201,4000,male,2009
Gentoo,Biscoe,46.1,13.2,211,4500,female,2007
Gentoo,Biscoe,50,16.3,230,5700,male,2007
Gentoo,Biscoe,48.7,14.1,210,4450,female,2007
Gentoo,Biscoe,50,15.2,218,5700,male,2007
Gentoo,Biscoe,47.6,14.5,215,5400,male,2007
Gentoo,Biscoe,46.5,13.5,210,4550,female,2007
Gentoo,Biscoe,45.4,14.6,211,4800,female,2007
Gentoo,Biscoe,46.7,15.3,219,5200,male,2007
Gentoo,Biscoe,43.3,13.4,209,4400,female,2007
Gentoo,Biscoe,46.8,15.4,215,5150,male,2007
Gentoo,Biscoe,40.9,13.7,214,4650,female,2007
Gentoo,Biscoe,49,16.1,216,5550,male,2007
Gentoo,Biscoe,45.5,13.7,214,4650,female,2007
Gentoo,Biscoe,48.4,14.6,213,5850,male,2007
Gentoo,Biscoe,45.8,14.6,210,4200,female,2007
Gentoo,Biscoe,49.3,15.7,217,5850,male,2007
Gentoo,Biscoe,42,13.5,210,4150,female,2007
Gentoo,Biscoe,49.2,15.2,221,6300,male,2007
Gentoo,Biscoe,46.2,14.5,209,4800,female,2007
Gentoo,Biscoe,48.7,15.1,222,5350,male,2007
Gentoo,Biscoe,50.2,14.3,218,5700,male,2007
Gentoo,Biscoe,45.1,14.5,215,5000,female,2007
Gentoo,Biscoe,46.5,14.5,213,4400,female,2007
Gentoo,Biscoe,46.3,15.8,215,5050,male,2007
Gentoo,Biscoe,42.9,13.1,215,5000,female,2007
Gentoo,Biscoe,46.1,15.1,215,5100,male,2007
Gentoo,Biscoe,44.5,14.3,216,4100,NA,2007
Gentoo,Biscoe,47.8,15,215,5650,male,2007
Gentoo,Biscoe,48.2,14.3,210,4600,female,2007
Gentoo,Biscoe,50,15.3,220,5550,male,2007
Gentoo,Biscoe,47.3,15.3,222,5250,male,2007
Gentoo,Biscoe,42.8,14.2,209,4700,female,2007
Gentoo,Biscoe,45.1,14.5,207,5050,female,2007
Gentoo,Biscoe,59.6,17,230,6050,male,2007
Gentoo,Biscoe,49.1,14.8,220,5150,female,2008
Gentoo,Biscoe,48.4,16.3,220,5400,male,2008
Gentoo,Biscoe,42.6,13.7,213,4950,female,2008
Gentoo,Biscoe,44.4,17.3,219,5250,male,2008
Gentoo,Biscoe,44,13.6,208,4350,female,2008
Gentoo,Biscoe,48.7,15.7,208,5350,male,2008
Gentoo,Biscoe,42.7,13.7,208,3950,female,2008
Gentoo,Biscoe,49.6,16,225,5700,male,2008
Gentoo,Biscoe,45.3,13.7,210,4300,female,2008
Gentoo,Biscoe,49.6,15,216,4750,male,2008
Gentoo,Biscoe,50.5,15.9,222,5550,male,2008
Gentoo,Biscoe,43.6,13.9,217,4900,female,2008
Gentoo,Biscoe,45.5,13.9,210,4200,female,2008
Gentoo,Biscoe,50.5,15.9,225,5400,male,2008
Gentoo,Biscoe,44.9,13.3,213,5100,female,2008
Gentoo,Biscoe,45.2,15.8,215,5300,male,2008
Gentoo,Biscoe,46.6,14.2,210,4850,female,2008
Gentoo,Biscoe,48.5,14.1,220,5300,male,2008
Gentoo,Biscoe,45.1,14.4,210,4400,female,2008
Gentoo,Biscoe,50.1,15,225,5000,male,2008
Gentoo,Biscoe,46.5,14.4,217,4900,female,2008
Gentoo,Biscoe,45,15.4,220,5050,male,2008
Gentoo,Biscoe,43.8,13.9,208,4300,female,2008
Gentoo,Biscoe,45.5,15,220,5000,male,2008
Gentoo,Biscoe,43.2,14.5,208,4450,female,2008
Gentoo,Biscoe,50.4,15.3,224,5550,male,2008
Gentoo,Biscoe,45.3,13.8,208,4200,female,2008
Gentoo,Biscoe,46.2,14.9,221,5300,male,2008
Gentoo,Biscoe,45.7,13.9,214,4400,female,2008
Gentoo,Biscoe,54.3,15.7,231,5650,male,2008
Gentoo,Biscoe,45.8,14.2,219,4700,female,2008
Gentoo,Biscoe,49.8,16.8,230,5700,male,2008
Gentoo,Biscoe,46.2,14.4,214,4650,NA,2008
Gentoo,Biscoe,49.5,16.2,229,5800,male,2008
Gentoo,Biscoe,43.5,14.2,220,4700,female,2008
Gentoo,Biscoe,50.7,15,223,5550,male,2008
Gentoo,Biscoe,47.7,15,216,4750,female,2008
Gentoo,Biscoe,46.4,15.6,221,5000,male,2008
Gentoo,Biscoe,48.2,15.6,221,5100,male,2008
Gentoo,Biscoe,46.5,14.8,217,5200,female,2008
Gentoo,Biscoe,46.4,15,216,4700,female,2008
Gentoo,Biscoe,48.6,16,230,5800,male,2008
Gentoo,Biscoe,47.5,14.2,209,4600,female,2008
Gentoo,Biscoe,51.1,16.3,220,6000,male,2008
Gentoo,Biscoe,45.2,13.8,215,4750,female,2008
Gentoo,Biscoe,45.2,16.4,223,5950,male,2008
Gentoo,Biscoe,49.1,14.5,212,4625,female,2009
Gentoo,Biscoe,52.5,15.6,221,5450,male,2009
Gentoo,Biscoe,47.4,14.6,212,4725,female,2009
Gentoo,Biscoe,50,15.9,224,5350,male,2009
Gentoo,Biscoe,44.9,13.8,212,4750,female,2009
Gentoo,Biscoe,50.8,17.3,228,5600,male,2009
Gentoo,Biscoe,43.4,14.4,218,4600,female,2009
Gentoo,Biscoe,51.3,14.2,218,5300,male,2009
Gentoo,Biscoe,47.5,14,212,4875,female,2009
Gentoo,Biscoe,52.1,17,230,5550,male,2009
Gentoo,Biscoe,47.5,15,218,4950,female,2009
Gentoo,Biscoe,52.2,17.1,228,5400,male,2009
Gentoo,Biscoe,45.5,14.5,212,4750,female,2009
Gentoo,Biscoe,49.5,16.1,224,5650,male,2009
Gentoo,Biscoe,44.5,14.7,214,4850,female,2009
Gentoo,Biscoe,50.8,15.7,226,5200,male,2009
Gentoo,Biscoe,49.4,15.8,216,4925,male,2009
Gentoo,Biscoe,46.9,14.6,222,4875,female,2009
Gentoo,Biscoe,48.4,14.4,203,4625,female,2009
Gentoo,Biscoe,51.1,16.5,225,5250,male,2009
Gentoo,Biscoe,48.5,15,219,4850,female,2009
Gentoo,Biscoe,55.9,17,228,5600,male,2009
Gentoo,Biscoe,47.2,15.5,215,4975,female,2009
Gentoo,Biscoe,49.1,15,228,5500,male,2009
Gentoo,Biscoe,47.3,13.8,216,4725,NA,2009
Gentoo,Biscoe,46.8,16.1,215,5500,male,2009
Gentoo,Biscoe,41.7,14.7,210,4700,female,2009
Gentoo,Biscoe,53.4,15.8,219,5500,male,2009
Gentoo,Biscoe,43.3,14,208,4575,female,2009
Gentoo,Biscoe,48.1,15.1,209,5500,male,2009
Gentoo,Biscoe,50.5,15.2,216,5000,female,2009
Gentoo,Biscoe,49.8,15.9,229,5950,male,2009
Gentoo,Biscoe,43.5,15.2,213,4650,female,2009
Gentoo,Biscoe,51.5,16.3,230,5500,male,2009
Gentoo,Biscoe,46.2,14.1,217,4375,female,2009
Gentoo,Biscoe,55.1,16,230,5850,male,2009
Gentoo,Biscoe,44.5,15.7,217,4875,NA,2009
Gentoo,Biscoe,48.8,16.2,222,6000,male,2009
Gentoo,Biscoe,47.2,13.7,214,4925,female,2009
Gentoo,Biscoe,NA,NA,NA,NA,NA,2009
Gentoo,Biscoe,46.8,14.3,215,4850,female,2009
Gentoo,Biscoe,50.4,15.7,222,5750,male,2009
Gentoo,Biscoe,45.2,14.8,212,5200,female,2009
Gentoo,Biscoe,49.9,16.1,213,5400,male,2009
Chinstrap,Dream,46.5,17.9,192,3500,female,2007
Chinstrap,Dream,50,19.5,196,3900,male,2007
Chinstrap,Dream,51.3,19.2,193,3650,male,2007
Chinstrap,Dream,45.4,18.7,188,3525,female,2007
Chinstrap,Dream,52.7,19.8,197,3725,male,2007
Chinstrap,Dream,45.2,17.8,198,3950,female,2007
Chinstrap,Dream,46.1,18.2,178,3250,female,2007
Chinstrap,Dream,51.3,18.2,197,3750,male,2007
Chinstrap,Dream,46,18.9,195,4150,female,2007
Chinstrap,Dream,51.3,19.9,198,3700,male,2007
Chinstrap,Dream,46.6,17.8,193,3800,female,2007
Chinstrap,Dream,51.7,20.3,194,3775,male,2007
Chinstrap,Dream,47,17.3,185,3700,female,2007
Chinstrap,Dream,52,18.1,201,4050,male,2007
Chinstrap,Dream,45.9,17.1,190,3575,female,2007
Chinstrap,Dream,50.5,19.6,201,4050,male,2007
Chinstrap,Dream,50.3,20,197,3300,male,2007
Chinstrap,Dream,58,17.8,181,3700,female,2007
Chinstrap,Dream,46.4,18.6,190,3450,female,2007
Chinstrap,Dream,49.2,18.2,195,4400,male,2007
Chinstrap,Dream,42.4,17.3,181,3600,female,2007
Chinstrap,Dream,48.5,17.5,191,3400,male,2007
Chinstrap,Dream,43.2,16.6,187,2900,female,2007
Chinstrap,Dream,50.6,19.4,193,3800,male,2007
Chinstrap,Dream,46.7,17.9,195,3300,female,2007
Chinstrap,Dream,52,19,197,4150,male,2007
Chinstrap,Dream,50.5,18.4,200,3400,female,2008
Chinstrap,Dream,49.5,19,200,3800,male,2008
Chinstrap,Dream,46.4,17.8,191,3700,female,2008
Chinstrap,Dream,52.8,20,205,4550,male,2008
Chinstrap,Dream,40.9,16.6,187,3200,female,2008
Chinstrap,Dream,54.2,20.8,201,4300,male,2008
Chinstrap,Dream,42.5,16.7,187,3350,female,2008
Chinstrap,Dream,51,18.8,203,4100,male,2008
Chinstrap,Dream,49.7,18.6,195,3600,male,2008
Chinstrap,Dream,47.5,16.8,199,3900,female,2008
Chinstrap,Dream,47.6,18.3,195,3850,female,2008
Chinstrap,Dream,52,20.7,210,4800,male,2008
Chinstrap,Dream,46.9,16.6,192,2700,female,2008
Chinstrap,Dream,53.5,19.9,205,4500,male,2008
Chinstrap,Dream,49,19.5,210,3950,male,2008
Chinstrap,Dream,46.2,17.5,187,3650,female,2008
Chinstrap,Dream,50.9,19.1,196,3550,male,2008
Chinstrap,Dream,45.5,17,196,3500,female,2008
Chinstrap,Dream,50.9,17.9,196,3675,female,2009
Chinstrap,Dream,50.8,18.5,201,4450,male,2009
Chinstrap,Dream,50.1,17.9,190,3400,female,2009
Chinstrap,Dream,49,19.6,212,4300,male,2009
Chinstrap,Dream,51.5,18.7,187,3250,male,2009
Chinstrap,Dream,49.8,17.3,198,3675,female,2009
Chinstrap,Dream,48.1,16.4,199,3325,female,2009
Chinstrap,Dream,51.4,19,201,3950,male,2009
Chinstrap,Dream,45.7,17.3,193,3600,female,2009
Chinstrap,Dream,50.7,19.7,203,4050,male,2009
Chinstrap,Dream,42.5,17.3,187,3350,female,2009
Chinstrap,Dream,52.2,18.8,197,3450,male,2009
Chinstrap,Dream,45.2,16.6,191,3250,female,2009
Chinstrap,Dream,49.3,19.9,203,4050,male,2009
Chinstrap,Dream,50.2,18.8,202,3800,male,2009
Chinstrap,Dream,45.6,19.4,194,3525,female,2009
Chinstrap,Dream,51.9,19.5,206,3950,male,2009
Chinstrap,Dream,46.8,16.5,189,3650,female,2009
Chinstrap,Dream,45.7,17,195,3650,female,2009
Chinstrap,Dream,55.8,19.8,207,4000,male,2009
Chinstrap,Dream,43.5,18.1,202,3400,female,2009
Chinstrap,Dream,49.6,18.2,193,3775,male,2009
Chinstrap,Dream,50.8,19,210,4100,male,2009
Chinstrap,Dream,50.2,18.7,198,3775,female,2009

## file: plots.py
from plotnine import ggplot, geom_density, aes, theme_light, geom_point, stat_smooth


def dist_plot(df):
    plot = (
        ggplot(df, aes(x="body_mass", fill="species"))
        + geom_density(alpha=0.2)
        + theme_light()
    )
    return plot


def scatter_plot(df, trend_line=False):
    plot = (
        ggplot(
            df,
            aes(
                x="bill_length",
                y="bill_depth",
                color="species",
                group="species",
            ),
        )
        + geom_point()
        + theme_light()
    )

    if trend_line:
        plot = plot + stat_smooth()

    return plot

Solution

Exercise

Extract reactive calculations from this app to reduce repetition and speed up the app. There are several good solutions to this problem, but the majority of people end up with two reactive calculations.

#| standalone: true
#| components: [editor, viewer]
#| layout: horizontal
#| viewerHeight: 800
from shiny import App, render, ui, reactive
import pandas as pd
from pathlib import Path
from plots import dist_plot

infile = Path(__file__).parent / "penguins.csv"
penguins = pd.read_csv(infile)

app_ui = ui.page_fluid(
    ui.panel_title("Hello Penguins!"),
    ui.layout_sidebar(
        ui.panel_sidebar(
            ui.input_numeric("sample", "Sample Size", value=100),
            ui.input_slider(
                "mass",
                "Mass",
                2000,
                8000,
                6000,
            ),
            ui.input_selectize(
                "columns",
                "Columns",
                choices=penguins.columns.tolist(),
                selected=["species", "island"],
                multiple=True,
            ),
        ),
        ui.panel_main(
            ui.output_plot("mass_plot"),
            ui.output_text("row_count"),
            ui.output_data_frame("species_summary"),
        ),
    ),
)


def server(input, output, session):
    @reactive.Calc
    def sampled_df():
        return sample_data(penguins.copy(), input.sample())

    @reactive.Calc
    def filtered_df():
        df = sampled_df()
        return df.loc[df["body_mass"] < input.mass()]

    @render.plot
    def mass_plot():
        return dist_plot(sampled_df())

    @render.text
    def row_count():
        return f"{filtered_df().shape[0]} rows in filtered sample"

    @render.data_frame
    def species_summary():
        return filtered_df()[list(input.columns())]


app = App(app_ui, server)


def sample_data(data: pd.DataFrame, n: int) -> pd.DataFrame:
    # This loop is here to simulate a lengthy computation
    # pyodide does not support time.sleep() so this is the
    # workaround.
    for i in range(10000):
        out = data.sample(n, replace=True)
    return out

## file: penguins.csv
species,island,bill_length,bill_depth,flipper_length,body_mass,sex,year
Adelie,Torgersen,39.1,18.7,181,3750,male,2007
Adelie,Torgersen,39.5,17.4,186,3800,female,2007
Adelie,Torgersen,40.3,18,195,3250,female,2007
Adelie,Torgersen,NA,NA,NA,NA,NA,2007
Adelie,Torgersen,36.7,19.3,193,3450,female,2007
Adelie,Torgersen,39.3,20.6,190,3650,male,2007
Adelie,Torgersen,38.9,17.8,181,3625,female,2007
Adelie,Torgersen,39.2,19.6,195,4675,male,2007
Adelie,Torgersen,34.1,18.1,193,3475,NA,2007
Adelie,Torgersen,42,20.2,190,4250,NA,2007
Adelie,Torgersen,37.8,17.1,186,3300,NA,2007
Adelie,Torgersen,37.8,17.3,180,3700,NA,2007
Adelie,Torgersen,41.1,17.6,182,3200,female,2007
Adelie,Torgersen,38.6,21.2,191,3800,male,2007
Adelie,Torgersen,34.6,21.1,198,4400,male,2007
Adelie,Torgersen,36.6,17.8,185,3700,female,2007
Adelie,Torgersen,38.7,19,195,3450,female,2007
Adelie,Torgersen,42.5,20.7,197,4500,male,2007
Adelie,Torgersen,34.4,18.4,184,3325,female,2007
Adelie,Torgersen,46,21.5,194,4200,male,2007
Adelie,Biscoe,37.8,18.3,174,3400,female,2007
Adelie,Biscoe,37.7,18.7,180,3600,male,2007
Adelie,Biscoe,35.9,19.2,189,3800,female,2007
Adelie,Biscoe,38.2,18.1,185,3950,male,2007
Adelie,Biscoe,38.8,17.2,180,3800,male,2007
Adelie,Biscoe,35.3,18.9,187,3800,female,2007
Adelie,Biscoe,40.6,18.6,183,3550,male,2007
Adelie,Biscoe,40.5,17.9,187,3200,female,2007
Adelie,Biscoe,37.9,18.6,172,3150,female,2007
Adelie,Biscoe,40.5,18.9,180,3950,male,2007
Adelie,Dream,39.5,16.7,178,3250,female,2007
Adelie,Dream,37.2,18.1,178,3900,male,2007
Adelie,Dream,39.5,17.8,188,3300,female,2007
Adelie,Dream,40.9,18.9,184,3900,male,2007
Adelie,Dream,36.4,17,195,3325,female,2007
Adelie,Dream,39.2,21.1,196,4150,male,2007
Adelie,Dream,38.8,20,190,3950,male,2007
Adelie,Dream,42.2,18.5,180,3550,female,2007
Adelie,Dream,37.6,19.3,181,3300,female,2007
Adelie,Dream,39.8,19.1,184,4650,male,2007
Adelie,Dream,36.5,18,182,3150,female,2007
Adelie,Dream,40.8,18.4,195,3900,male,2007
Adelie,Dream,36,18.5,186,3100,female,2007
Adelie,Dream,44.1,19.7,196,4400,male,2007
Adelie,Dream,37,16.9,185,3000,female,2007
Adelie,Dream,39.6,18.8,190,4600,male,2007
Adelie,Dream,41.1,19,182,3425,male,2007
Adelie,Dream,37.5,18.9,179,2975,NA,2007
Adelie,Dream,36,17.9,190,3450,female,2007
Adelie,Dream,42.3,21.2,191,4150,male,2007
Adelie,Biscoe,39.6,17.7,186,3500,female,2008
Adelie,Biscoe,40.1,18.9,188,4300,male,2008
Adelie,Biscoe,35,17.9,190,3450,female,2008
Adelie,Biscoe,42,19.5,200,4050,male,2008
Adelie,Biscoe,34.5,18.1,187,2900,female,2008
Adelie,Biscoe,41.4,18.6,191,3700,male,2008
Adelie,Biscoe,39,17.5,186,3550,female,2008
Adelie,Biscoe,40.6,18.8,193,3800,male,2008
Adelie,Biscoe,36.5,16.6,181,2850,female,2008
Adelie,Biscoe,37.6,19.1,194,3750,male,2008
Adelie,Biscoe,35.7,16.9,185,3150,female,2008
Adelie,Biscoe,41.3,21.1,195,4400,male,2008
Adelie,Biscoe,37.6,17,185,3600,female,2008
Adelie,Biscoe,41.1,18.2,192,4050,male,2008
Adelie,Biscoe,36.4,17.1,184,2850,female,2008
Adelie,Biscoe,41.6,18,192,3950,male,2008
Adelie,Biscoe,35.5,16.2,195,3350,female,2008
Adelie,Biscoe,41.1,19.1,188,4100,male,2008
Adelie,Torgersen,35.9,16.6,190,3050,female,2008
Adelie,Torgersen,41.8,19.4,198,4450,male,2008
Adelie,Torgersen,33.5,19,190,3600,female,2008
Adelie,Torgersen,39.7,18.4,190,3900,male,2008
Adelie,Torgersen,39.6,17.2,196,3550,female,2008
Adelie,Torgersen,45.8,18.9,197,4150,male,2008
Adelie,Torgersen,35.5,17.5,190,3700,female,2008
Adelie,Torgersen,42.8,18.5,195,4250,male,2008
Adelie,Torgersen,40.9,16.8,191,3700,female,2008
Adelie,Torgersen,37.2,19.4,184,3900,male,2008
Adelie,Torgersen,36.2,16.1,187,3550,female,2008
Adelie,Torgersen,42.1,19.1,195,4000,male,2008
Adelie,Torgersen,34.6,17.2,189,3200,female,2008
Adelie,Torgersen,42.9,17.6,196,4700,male,2008
Adelie,Torgersen,36.7,18.8,187,3800,female,2008
Adelie,Torgersen,35.1,19.4,193,4200,male,2008
Adelie,Dream,37.3,17.8,191,3350,female,2008
Adelie,Dream,41.3,20.3,194,3550,male,2008
Adelie,Dream,36.3,19.5,190,3800,male,2008
Adelie,Dream,36.9,18.6,189,3500,female,2008
Adelie,Dream,38.3,19.2,189,3950,male,2008
Adelie,Dream,38.9,18.8,190,3600,female,2008
Adelie,Dream,35.7,18,202,3550,female,2008
Adelie,Dream,41.1,18.1,205,4300,male,2008
Adelie,Dream,34,17.1,185,3400,female,2008
Adelie,Dream,39.6,18.1,186,4450,male,2008
Adelie,Dream,36.2,17.3,187,3300,female,2008
Adelie,Dream,40.8,18.9,208,4300,male,2008
Adelie,Dream,38.1,18.6,190,3700,female,2008
Adelie,Dream,40.3,18.5,196,4350,male,2008
Adelie,Dream,33.1,16.1,178,2900,female,2008
Adelie,Dream,43.2,18.5,192,4100,male,2008
Adelie,Biscoe,35,17.9,192,3725,female,2009
Adelie,Biscoe,41,20,203,4725,male,2009
Adelie,Biscoe,37.7,16,183,3075,female,2009
Adelie,Biscoe,37.8,20,190,4250,male,2009
Adelie,Biscoe,37.9,18.6,193,2925,female,2009
Adelie,Biscoe,39.7,18.9,184,3550,male,2009
Adelie,Biscoe,38.6,17.2,199,3750,female,2009
Adelie,Biscoe,38.2,20,190,3900,male,2009
Adelie,Biscoe,38.1,17,181,3175,female,2009
Adelie,Biscoe,43.2,19,197,4775,male,2009
Adelie,Biscoe,38.1,16.5,198,3825,female,2009
Adelie,Biscoe,45.6,20.3,191,4600,male,2009
Adelie,Biscoe,39.7,17.7,193,3200,female,2009
Adelie,Biscoe,42.2,19.5,197,4275,male,2009
Adelie,Biscoe,39.6,20.7,191,3900,female,2009
Adelie,Biscoe,42.7,18.3,196,4075,male,2009
Adelie,Torgersen,38.6,17,188,2900,female,2009
Adelie,Torgersen,37.3,20.5,199,3775,male,2009
Adelie,Torgersen,35.7,17,189,3350,female,2009
Adelie,Torgersen,41.1,18.6,189,3325,male,2009
Adelie,Torgersen,36.2,17.2,187,3150,female,2009
Adelie,Torgersen,37.7,19.8,198,3500,male,2009
Adelie,Torgersen,40.2,17,176,3450,female,2009
Adelie,Torgersen,41.4,18.5,202,3875,male,2009
Adelie,Torgersen,35.2,15.9,186,3050,female,2009
Adelie,Torgersen,40.6,19,199,4000,male,2009
Adelie,Torgersen,38.8,17.6,191,3275,female,2009
Adelie,Torgersen,41.5,18.3,195,4300,male,2009
Adelie,Torgersen,39,17.1,191,3050,female,2009
Adelie,Torgersen,44.1,18,210,4000,male,2009
Adelie,Torgersen,38.5,17.9,190,3325,female,2009
Adelie,Torgersen,43.1,19.2,197,3500,male,2009
Adelie,Dream,36.8,18.5,193,3500,female,2009
Adelie,Dream,37.5,18.5,199,4475,male,2009
Adelie,Dream,38.1,17.6,187,3425,female,2009
Adelie,Dream,41.1,17.5,190,3900,male,2009
Adelie,Dream,35.6,17.5,191,3175,female,2009
Adelie,Dream,40.2,20.1,200,3975,male,2009
Adelie,Dream,37,16.5,185,3400,female,2009
Adelie,Dream,39.7,17.9,193,4250,male,2009
Adelie,Dream,40.2,17.1,193,3400,female,2009
Adelie,Dream,40.6,17.2,187,3475,male,2009
Adelie,Dream,32.1,15.5,188,3050,female,2009
Adelie,Dream,40.7,17,190,3725,male,2009
Adelie,Dream,37.3,16.8,192,3000,female,2009
Adelie,Dream,39,18.7,185,3650,male,2009
Adelie,Dream,39.2,18.6,190,4250,male,2009
Adelie,Dream,36.6,18.4,184,3475,female,2009
Adelie,Dream,36,17.8,195,3450,female,2009
Adelie,Dream,37.8,18.1,193,3750,male,2009
Adelie,Dream,36,17.1,187,3700,female,2009
Adelie,Dream,41.5,18.5,201,4000,male,2009
Gentoo,Biscoe,46.1,13.2,211,4500,female,2007
Gentoo,Biscoe,50,16.3,230,5700,male,2007
Gentoo,Biscoe,48.7,14.1,210,4450,female,2007
Gentoo,Biscoe,50,15.2,218,5700,male,2007
Gentoo,Biscoe,47.6,14.5,215,5400,male,2007
Gentoo,Biscoe,46.5,13.5,210,4550,female,2007
Gentoo,Biscoe,45.4,14.6,211,4800,female,2007
Gentoo,Biscoe,46.7,15.3,219,5200,male,2007
Gentoo,Biscoe,43.3,13.4,209,4400,female,2007
Gentoo,Biscoe,46.8,15.4,215,5150,male,2007
Gentoo,Biscoe,40.9,13.7,214,4650,female,2007
Gentoo,Biscoe,49,16.1,216,5550,male,2007
Gentoo,Biscoe,45.5,13.7,214,4650,female,2007
Gentoo,Biscoe,48.4,14.6,213,5850,male,2007
Gentoo,Biscoe,45.8,14.6,210,4200,female,2007
Gentoo,Biscoe,49.3,15.7,217,5850,male,2007
Gentoo,Biscoe,42,13.5,210,4150,female,2007
Gentoo,Biscoe,49.2,15.2,221,6300,male,2007
Gentoo,Biscoe,46.2,14.5,209,4800,female,2007
Gentoo,Biscoe,48.7,15.1,222,5350,male,2007
Gentoo,Biscoe,50.2,14.3,218,5700,male,2007
Gentoo,Biscoe,45.1,14.5,215,5000,female,2007
Gentoo,Biscoe,46.5,14.5,213,4400,female,2007
Gentoo,Biscoe,46.3,15.8,215,5050,male,2007
Gentoo,Biscoe,42.9,13.1,215,5000,female,2007
Gentoo,Biscoe,46.1,15.1,215,5100,male,2007
Gentoo,Biscoe,44.5,14.3,216,4100,NA,2007
Gentoo,Biscoe,47.8,15,215,5650,male,2007
Gentoo,Biscoe,48.2,14.3,210,4600,female,2007
Gentoo,Biscoe,50,15.3,220,5550,male,2007
Gentoo,Biscoe,47.3,15.3,222,5250,male,2007
Gentoo,Biscoe,42.8,14.2,209,4700,female,2007
Gentoo,Biscoe,45.1,14.5,207,5050,female,2007
Gentoo,Biscoe,59.6,17,230,6050,male,2007
Gentoo,Biscoe,49.1,14.8,220,5150,female,2008
Gentoo,Biscoe,48.4,16.3,220,5400,male,2008
Gentoo,Biscoe,42.6,13.7,213,4950,female,2008
Gentoo,Biscoe,44.4,17.3,219,5250,male,2008
Gentoo,Biscoe,44,13.6,208,4350,female,2008
Gentoo,Biscoe,48.7,15.7,208,5350,male,2008
Gentoo,Biscoe,42.7,13.7,208,3950,female,2008
Gentoo,Biscoe,49.6,16,225,5700,male,2008
Gentoo,Biscoe,45.3,13.7,210,4300,female,2008
Gentoo,Biscoe,49.6,15,216,4750,male,2008
Gentoo,Biscoe,50.5,15.9,222,5550,male,2008
Gentoo,Biscoe,43.6,13.9,217,4900,female,2008
Gentoo,Biscoe,45.5,13.9,210,4200,female,2008
Gentoo,Biscoe,50.5,15.9,225,5400,male,2008
Gentoo,Biscoe,44.9,13.3,213,5100,female,2008
Gentoo,Biscoe,45.2,15.8,215,5300,male,2008
Gentoo,Biscoe,46.6,14.2,210,4850,female,2008
Gentoo,Biscoe,48.5,14.1,220,5300,male,2008
Gentoo,Biscoe,45.1,14.4,210,4400,female,2008
Gentoo,Biscoe,50.1,15,225,5000,male,2008
Gentoo,Biscoe,46.5,14.4,217,4900,female,2008
Gentoo,Biscoe,45,15.4,220,5050,male,2008
Gentoo,Biscoe,43.8,13.9,208,4300,female,2008
Gentoo,Biscoe,45.5,15,220,5000,male,2008
Gentoo,Biscoe,43.2,14.5,208,4450,female,2008
Gentoo,Biscoe,50.4,15.3,224,5550,male,2008
Gentoo,Biscoe,45.3,13.8,208,4200,female,2008
Gentoo,Biscoe,46.2,14.9,221,5300,male,2008
Gentoo,Biscoe,45.7,13.9,214,4400,female,2008
Gentoo,Biscoe,54.3,15.7,231,5650,male,2008
Gentoo,Biscoe,45.8,14.2,219,4700,female,2008
Gentoo,Biscoe,49.8,16.8,230,5700,male,2008
Gentoo,Biscoe,46.2,14.4,214,4650,NA,2008
Gentoo,Biscoe,49.5,16.2,229,5800,male,2008
Gentoo,Biscoe,43.5,14.2,220,4700,female,2008
Gentoo,Biscoe,50.7,15,223,5550,male,2008
Gentoo,Biscoe,47.7,15,216,4750,female,2008
Gentoo,Biscoe,46.4,15.6,221,5000,male,2008
Gentoo,Biscoe,48.2,15.6,221,5100,male,2008
Gentoo,Biscoe,46.5,14.8,217,5200,female,2008
Gentoo,Biscoe,46.4,15,216,4700,female,2008
Gentoo,Biscoe,48.6,16,230,5800,male,2008
Gentoo,Biscoe,47.5,14.2,209,4600,female,2008
Gentoo,Biscoe,51.1,16.3,220,6000,male,2008
Gentoo,Biscoe,45.2,13.8,215,4750,female,2008
Gentoo,Biscoe,45.2,16.4,223,5950,male,2008
Gentoo,Biscoe,49.1,14.5,212,4625,female,2009
Gentoo,Biscoe,52.5,15.6,221,5450,male,2009
Gentoo,Biscoe,47.4,14.6,212,4725,female,2009
Gentoo,Biscoe,50,15.9,224,5350,male,2009
Gentoo,Biscoe,44.9,13.8,212,4750,female,2009
Gentoo,Biscoe,50.8,17.3,228,5600,male,2009
Gentoo,Biscoe,43.4,14.4,218,4600,female,2009
Gentoo,Biscoe,51.3,14.2,218,5300,male,2009
Gentoo,Biscoe,47.5,14,212,4875,female,2009
Gentoo,Biscoe,52.1,17,230,5550,male,2009
Gentoo,Biscoe,47.5,15,218,4950,female,2009
Gentoo,Biscoe,52.2,17.1,228,5400,male,2009
Gentoo,Biscoe,45.5,14.5,212,4750,female,2009
Gentoo,Biscoe,49.5,16.1,224,5650,male,2009
Gentoo,Biscoe,44.5,14.7,214,4850,female,2009
Gentoo,Biscoe,50.8,15.7,226,5200,male,2009
Gentoo,Biscoe,49.4,15.8,216,4925,male,2009
Gentoo,Biscoe,46.9,14.6,222,4875,female,2009
Gentoo,Biscoe,48.4,14.4,203,4625,female,2009
Gentoo,Biscoe,51.1,16.5,225,5250,male,2009
Gentoo,Biscoe,48.5,15,219,4850,female,2009
Gentoo,Biscoe,55.9,17,228,5600,male,2009
Gentoo,Biscoe,47.2,15.5,215,4975,female,2009
Gentoo,Biscoe,49.1,15,228,5500,male,2009
Gentoo,Biscoe,47.3,13.8,216,4725,NA,2009
Gentoo,Biscoe,46.8,16.1,215,5500,male,2009
Gentoo,Biscoe,41.7,14.7,210,4700,female,2009
Gentoo,Biscoe,53.4,15.8,219,5500,male,2009
Gentoo,Biscoe,43.3,14,208,4575,female,2009
Gentoo,Biscoe,48.1,15.1,209,5500,male,2009
Gentoo,Biscoe,50.5,15.2,216,5000,female,2009
Gentoo,Biscoe,49.8,15.9,229,5950,male,2009
Gentoo,Biscoe,43.5,15.2,213,4650,female,2009
Gentoo,Biscoe,51.5,16.3,230,5500,male,2009
Gentoo,Biscoe,46.2,14.1,217,4375,female,2009
Gentoo,Biscoe,55.1,16,230,5850,male,2009
Gentoo,Biscoe,44.5,15.7,217,4875,NA,2009
Gentoo,Biscoe,48.8,16.2,222,6000,male,2009
Gentoo,Biscoe,47.2,13.7,214,4925,female,2009
Gentoo,Biscoe,NA,NA,NA,NA,NA,2009
Gentoo,Biscoe,46.8,14.3,215,4850,female,2009
Gentoo,Biscoe,50.4,15.7,222,5750,male,2009
Gentoo,Biscoe,45.2,14.8,212,5200,female,2009
Gentoo,Biscoe,49.9,16.1,213,5400,male,2009
Chinstrap,Dream,46.5,17.9,192,3500,female,2007
Chinstrap,Dream,50,19.5,196,3900,male,2007
Chinstrap,Dream,51.3,19.2,193,3650,male,2007
Chinstrap,Dream,45.4,18.7,188,3525,female,2007
Chinstrap,Dream,52.7,19.8,197,3725,male,2007
Chinstrap,Dream,45.2,17.8,198,3950,female,2007
Chinstrap,Dream,46.1,18.2,178,3250,female,2007
Chinstrap,Dream,51.3,18.2,197,3750,male,2007
Chinstrap,Dream,46,18.9,195,4150,female,2007
Chinstrap,Dream,51.3,19.9,198,3700,male,2007
Chinstrap,Dream,46.6,17.8,193,3800,female,2007
Chinstrap,Dream,51.7,20.3,194,3775,male,2007
Chinstrap,Dream,47,17.3,185,3700,female,2007
Chinstrap,Dream,52,18.1,201,4050,male,2007
Chinstrap,Dream,45.9,17.1,190,3575,female,2007
Chinstrap,Dream,50.5,19.6,201,4050,male,2007
Chinstrap,Dream,50.3,20,197,3300,male,2007
Chinstrap,Dream,58,17.8,181,3700,female,2007
Chinstrap,Dream,46.4,18.6,190,3450,female,2007
Chinstrap,Dream,49.2,18.2,195,4400,male,2007
Chinstrap,Dream,42.4,17.3,181,3600,female,2007
Chinstrap,Dream,48.5,17.5,191,3400,male,2007
Chinstrap,Dream,43.2,16.6,187,2900,female,2007
Chinstrap,Dream,50.6,19.4,193,3800,male,2007
Chinstrap,Dream,46.7,17.9,195,3300,female,2007
Chinstrap,Dream,52,19,197,4150,male,2007
Chinstrap,Dream,50.5,18.4,200,3400,female,2008
Chinstrap,Dream,49.5,19,200,3800,male,2008
Chinstrap,Dream,46.4,17.8,191,3700,female,2008
Chinstrap,Dream,52.8,20,205,4550,male,2008
Chinstrap,Dream,40.9,16.6,187,3200,female,2008
Chinstrap,Dream,54.2,20.8,201,4300,male,2008
Chinstrap,Dream,42.5,16.7,187,3350,female,2008
Chinstrap,Dream,51,18.8,203,4100,male,2008
Chinstrap,Dream,49.7,18.6,195,3600,male,2008
Chinstrap,Dream,47.5,16.8,199,3900,female,2008
Chinstrap,Dream,47.6,18.3,195,3850,female,2008
Chinstrap,Dream,52,20.7,210,4800,male,2008
Chinstrap,Dream,46.9,16.6,192,2700,female,2008
Chinstrap,Dream,53.5,19.9,205,4500,male,2008
Chinstrap,Dream,49,19.5,210,3950,male,2008
Chinstrap,Dream,46.2,17.5,187,3650,female,2008
Chinstrap,Dream,50.9,19.1,196,3550,male,2008
Chinstrap,Dream,45.5,17,196,3500,female,2008
Chinstrap,Dream,50.9,17.9,196,3675,female,2009
Chinstrap,Dream,50.8,18.5,201,4450,male,2009
Chinstrap,Dream,50.1,17.9,190,3400,female,2009
Chinstrap,Dream,49,19.6,212,4300,male,2009
Chinstrap,Dream,51.5,18.7,187,3250,male,2009
Chinstrap,Dream,49.8,17.3,198,3675,female,2009
Chinstrap,Dream,48.1,16.4,199,3325,female,2009
Chinstrap,Dream,51.4,19,201,3950,male,2009
Chinstrap,Dream,45.7,17.3,193,3600,female,2009
Chinstrap,Dream,50.7,19.7,203,4050,male,2009
Chinstrap,Dream,42.5,17.3,187,3350,female,2009
Chinstrap,Dream,52.2,18.8,197,3450,male,2009
Chinstrap,Dream,45.2,16.6,191,3250,female,2009
Chinstrap,Dream,49.3,19.9,203,4050,male,2009
Chinstrap,Dream,50.2,18.8,202,3800,male,2009
Chinstrap,Dream,45.6,19.4,194,3525,female,2009
Chinstrap,Dream,51.9,19.5,206,3950,male,2009
Chinstrap,Dream,46.8,16.5,189,3650,female,2009
Chinstrap,Dream,45.7,17,195,3650,female,2009
Chinstrap,Dream,55.8,19.8,207,4000,male,2009
Chinstrap,Dream,43.5,18.1,202,3400,female,2009
Chinstrap,Dream,49.6,18.2,193,3775,male,2009
Chinstrap,Dream,50.8,19,210,4100,male,2009
Chinstrap,Dream,50.2,18.7,198,3775,female,2009

## file: plots.py
from plotnine import ggplot, geom_density, aes, theme_light, geom_point, stat_smooth


def dist_plot(df):
    plot = (
        ggplot(df, aes(x="body_mass", fill="species"))
        + geom_density(alpha=0.2)
        + theme_light()
    )
    return plot


def scatter_plot(df, trend_line=False):
    plot = (
        ggplot(
            df,
            aes(
                x="bill_length",
                y="bill_depth",
                color="species",
                group="species",
            ),
        )
        + geom_point()
        + theme_light()
    )

    if trend_line:
        plot = plot + stat_smooth()

    return plot

The source code for this exercise is here.

Exercise 2.3

Draw the reactive graph for the above application