Code Editor for app.py

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

# Function to generate sample time series data
def generate_data(days):
    end_date = datetime.datetime.now()
    start_date = end_date - datetime.timedelta(days=days)
    dates = pd.date_range(start=start_date, end=end_date, freq='D')
    values = np.random.normal(loc=100, scale=15, size=len(dates))
    df = pd.DataFrame({
        'Date': dates,
        'Value': values
    })
    return df

# Initialize session state for data if not exists
if 'data' not in st.session_state:
    st.session_state.data = generate_data(30)  # Default 30 days

st.title('Dynamic Time Series Graph')

# Slider for selecting number of days
days = st.slider('Select number of days to display', 
                 min_value=7, 
                 max_value=90, 
                 value=30,
                 key='days_slider')

# Update the data when slider changes
if days != len(st.session_state.data):
    st.session_state.data = generate_data(days)

# Display the line chart
st.line_chart(
    st.session_state.data.set_index('Date')['Value']
)