app.py

import streamlit as st
import pandas as pd


import seaborn as sns
import matplotlib.pyplot as plt

# Apply the default theme and activate color codes
sns.set_theme()
sns.set(color_codes=True)


################### import dataset
penguins = sns.load_dataset("penguins")

########### set the title and subtitle
st.title("Differences between penguins")

st.subheader("My flipper is longer!!!")

########## we add image
st.image("https://raw.githubusercontent.com/allisonhorst/palmerpenguins/main/man/figures/lter_penguins.png")

############## we create filters for our interactive plot
with st.sidebar:
    st.subheader("Filters")

    all_species = sorted(penguins["species"].dropna().unique().tolist())
    selected_species = st.multiselect(
        "Species to show",
        options=all_species,
        default=all_species,
    )

    feature_options = {
        "Flipper length (mm)": "flipper_length_mm",
        "Bill length (mm)": "bill_length_mm",
        "Bill depth (mm)": "bill_depth_mm",
        "Body mass (g)": "body_mass_g",
    }
    feature_label = st.selectbox("Feature (x-axis)", list(feature_options.keys()))
    x_col = feature_options[feature_label]

    # KDE options
    fill = st.checkbox("Shade area", value=True)
    bw_adjust = st.slider("Smoothing (bw_adjust)", 0.2, 2.0, 1.0, 0.1)
    common_norm = st.checkbox("Normalize across species", value=False)

if not selected_species:
    st.info("Select at least one species to display the plot.")
else:
    data = penguins[penguins["species"].isin(selected_species)].dropna(subset=[x_col])

    g = sns.displot(
        data=data,
        x=x_col,
        kind="kde",
        hue="species",
        fill=fill,
        bw_adjust=bw_adjust,
        common_norm=common_norm,
        height=4,
        aspect=1.6,
    )
    fig = g.fig if hasattr(g, "fig") else g.figure
    st.pyplot(fig)
    plt.close(fig)

########  add button to save image
from io import BytesIO

buf = BytesIO()
fig.savefig(buf, format="png", dpi=200, bbox_inches="tight") 
buf.seek(0)
st.download_button(
    "Save image",
    data=buf,
    file_name=f"penguins_{x_col}.png",
    mime="image/png",
)

########### Footer
st.caption("Developed for SDS M1 course.")