Getting Started with Streamlit: Build Python Frontends in Minutes

    import streamlit as st
    import pandas as pd
    import numpy as np

    st.title("My First Streamlit App")
    st.write("Hello, world! 👋")

    # Displaying data
    df = pd.DataFrame({
        "Numbers": [1, 2, 3],
        "Squares": [1, 4, 9]
    })
    st.table(df)

    # Simple chart
    st.line_chart(np.random.randn(20, 2))

    import streamlit as st
    import time

    # Sidebar for navigation
    st.sidebar.title("Settings")
    option = st.sidebar.selectbox("Choose a dataset:", ["Sales", "Marketing", "HR"])

    # Interactive widgets
    age = st.slider("Select your age:", 0, 100, 25)
    st.write("Selected age:", age)

    # File upload
    uploaded_file = st.file_uploader("Upload a CSV", type="csv")
    if uploaded_file:
        import pandas as pd
        df = pd.read_csv(uploaded_file)
        st.dataframe(df)

    # Progress bar
    progress = st.progress(0)
    for i in range(100):
        time.sleep(0.01)
        progress.progress(i + 1)

    import streamlit as st
    import pandas as pd
    import time

    # ------------------------------
    # Data loading (with caching)
    # ------------------------------
    @st.cache_data
    def load_sample_data():
        # Simulate an expensive operation
        time.sleep(1)
        return pd.DataFrame({
            "Name": ["Alice", "Bob", "Charlie"],
            "Age": [25, 30, 35]
        })

    # ------------------------------
    # UI Components
    # ------------------------------
    def render_title():
        st.title("🚀 Best Practices Streamlit App")

    def render_form():
        with st.form("user_form"):
            name = st.text_input("Enter your name:")
            age = st.number_input("Enter your age:", min_value=0, max_value=120)
            submitted = st.form_submit_button("Submit")

            if submitted:
                if not name:
                    st.error("❌ Please enter your name.")
                else:
                    st.session_state["user"] = {"name": name, "age": age}
                    st.success(f"✅ Hello {name}, you are {age} years old.")

    def render_data_section():
        st.header("📊 Sample Data")
        df = load_sample_data()
        st.dataframe(df)

    def render_user_section():
        if "user" in st.session_state:
            st.header("🙋 User Info")
            user = st.session_state["user"]
            st.write(f"Name: **{user['name']}**")
            st.write(f"Age: **{user['age']}**")

    # ------------------------------
    # Main app logic
    # ------------------------------
    def main():
        render_title()
        render_form()
        render_user_section()
        render_data_section()

    if __name__ == "__main__":
        main()