Code Editor for app.py

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

# Cache the data loading
@st.cache_data
def load_data(url):
    return pd.read_csv(url)

# App title
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 the data
    df = load_data(url)
    
    # Controls
    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(5, len(df)))
    
    with col2:
        shuffle = st.checkbox("Randomly shuffle data")
    
    if shuffle:
        df = df.sample(frac=1).reset_index(drop=True)
    
    # Display the dataframe
    st.subheader("Data Preview")
    st.dataframe(df.head(n_rows))
    
    # Variable selection
    st.subheader("Visualization")
    columns = df.select_dtypes(include=['int64', 'float64', 'object']).columns
    
    col1, col2 = st.columns(2)
    with col1:
        var1 = st.selectbox("Select first variable", columns)
    with col2:
        var2 = st.selectbox("Select second variable", columns)
    
    # Determine plot type based on variable types
    var1_numeric = pd.api.types.is_numeric_dtype(df[var1])
    var2_numeric = pd.api.types.is_numeric_dtype(df[var2])
    
    if var1_numeric and var2_numeric:
        # Scatter plot for two numeric variables
        fig = px.scatter(df, x=var1, y=var2)
        st.plotly_chart(fig)
    elif var1_numeric and not var2_numeric:
        # Box plot for numeric vs categorical
        fig = px.box(df, x=var2, y=var1)
        st.plotly_chart(fig)
    elif not var1_numeric and var2_numeric:
        # Box plot for categorical vs numeric
        fig = px.box(df, x=var1, y=var2)
        st.plotly_chart(fig)
    else:
        # Bar plot for two categorical variables
        counts = df.groupby([var1, var2]).size().reset_index(name='count')
        fig = px.bar(counts, x=var1, y='count', color=var2, barmode='group')
        st.plotly_chart(fig)

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