streamlit-1-basic-application-structure

name	streamlit-1-basic-application-structure
description	Sub-skill of streamlit: 1. Basic Application Structure (+1).
version	1.0.0
category	data-analysis
type	reference
scripts_exempt	true

1. Basic Application Structure (+1)

1. Basic Application Structure

Minimal App (app.py):

import streamlit as st
import pandas as pd
import polars as pl

# Page configuration (must be first Streamlit command)
st.set_page_config(
    page_title="My Data App",
    page_icon="📊",
    layout="wide",
    initial_sidebar_state="expanded"
)

# Title and header
st.title("My Data Application")
st.header("Welcome to the Dashboard")
st.subheader("Data Analysis Section")

# Text elements
st.text("This is plain text")
st.markdown("**Bold** and *italic* text with [links](https://streamlit.io)")
st.caption("This is a caption for additional context")
st.code("print('Hello, Streamlit!')", language="python")

# Display data
df = pd.DataFrame({
    "Name": ["Alice", "Bob", "Charlie"],
    "Age": [25, 30, 35],
    "City": ["NYC", "LA", "Chicago"]
})

st.dataframe(df)  # Interactive table
st.table(df)       # Static table
st.json({"key": "value", "list": [1, 2, 3]})

# Metrics
col1, col2, col3 = st.columns(3)
col1.metric("Revenue", "$1.2M", "+12%")
col2.metric("Users", "10,234", "-2%")
col3.metric("Conversion", "3.2%", "+0.5%")

Run the app:

streamlit run app.py

2. Widgets and User Input

Input Widgets:

import streamlit as st
from datetime import datetime, date

# Text inputs
name = st.text_input("Enter your name", value="User")
bio = st.text_area("Tell us about yourself", height=100)
password = st.text_input("Password", type="password")

# Numeric inputs
age = st.number_input("Age", min_value=0, max_value=120, value=25, step=1)
price = st.slider("Price Range", 0.0, 100.0, (25.0, 75.0))  # Range slider
rating = st.slider("Rating", 1, 5, 3)

# Selection widgets
option = st.selectbox("Choose an option", ["Option A", "Option B", "Option C"])
options = st.multiselect("Select multiple", ["Red", "Green", "Blue"], default=["Red"])
radio_choice = st.radio("Pick one", ["Small", "Medium", "Large"], horizontal=True)

# Boolean inputs
agree = st.checkbox("I agree to the terms")
toggle = st.toggle("Enable feature")

# Date and time
selected_date = st.date_input("Select a date", value=date.today())
date_range = st.date_input(
    ,
    value=(date(, , ), date.today()),
    =
)
selected_time = st.time_input()


uploaded_file = st.file_uploader(, =[, ])
 uploaded_file   :
    df = pd.read_csv(uploaded_file)
    st.write()


color = st.color_picker(, )


 st.button():
    st.write()



 ():
     pd.DataFrame({: [, , ], : [, , ]})

csv = get_data().to_csv(index=)
st.download_button(
    label=,
    data=csv,
    file_name=,
    mime=
)