Code Editor for app.py

import streamlit as st
import pandas as pd
import plotly.express as px

# Function to load and cache data
@st.cache_data
def load_data(url):
    return pd.read_csv(url)

st.title("Data Visualization App")

# URL input
url = st.text_input(
    "Enter CSV URL",
    value="https://raw.githubusercontent.com/mwaskom/seaborn-data/master/penguins.csv"
)

try:
    # Load data
    df = load_data(url)
    
    # Control panel
    col1, col2 = st.columns(2)
    
    with col1:
        n_rows = st.number_input("Number of rows to display", 
                                min_value=1, 
                                max_value=len(df), 
                                value=min(10, len(df)))
    
    with col2:
        shuffle = st.checkbox("Randomly shuffle data")
    
    # Shuffle if requested
    if shuffle:
        df = df.sample(frac=1, random_state=42).reset_index(drop=True)
    
    # Display dataframe
    st.subheader("Data Preview")
    st.dataframe(df.head(n_rows))
    
    # Variable selection
    st.subheader("Visualization")
    cols = df.select_dtypes(include=['float64', 'int64']).columns.tolist()
    
    col1, col2 = st.columns(2)
    
    with col1:
        var1 = st.selectbox("Select first variable", cols)
    
    with col2:
        remaining_cols = [col for col in cols if col != var1]
        var2 = st.selectbox("Select second variable (optional)", 
                           ["None"] + remaining_cols)
    
    # Visualization logic
    if var2 == "None":
        # Single variable visualization
        fig = px.histogram(df, x=var1, title=f"Distribution of {var1}")
        st.plotly_chart(fig)
    else:
        # Two variables visualization
        fig = px.scatter(df, x=var1, y=var2, 
                        title=f"Scatter plot of {var1} vs {var2}")
        st.plotly_chart(fig)
        
        # Show correlation
        correlation = df[var1].corr(df[var2])
        st.write(f"Correlation between {var1} and {var2}: {correlation:.2f}")

except Exception as e:
    st.error(f"Error: {str(e)}")
    st.write("Please make sure the URL points to a valid CSV file.")