Code Editor for app.py

import streamlit as st
import plotly.express as px
import plotly.graph_objects as go
import pandas as pd
import numpy as np
from datetime import datetime, timedelta

# Create sample datetime data
if 'data' not in st.session_state:
    dates = pd.date_range(start='2023-01-01', end='2023-12-31', freq='D')
    values = np.random.randn(len(dates)).cumsum()
    st.session_state.data = pd.DataFrame({
        'date': dates,
        'value': values
    })

# Initialize stored selections if not exists
if 'stored_selections' not in st.session_state:
    st.session_state.stored_selections = pd.DataFrame(columns=['start_date', 'end_date'])

# Create the plot
fig = px.line(st.session_state.data, x='date', y='value', title='Time Series Data')

# Update layout to enable selection
fig.update_layout(
    dragmode='select',
    selectdirection='h',  # horizontal selection
    hovermode='x'
)

# Display the plot with selection enabled
selection = st.plotly_chart(
    fig,
    use_container_width=True,
    key="timeseries",
    on_select="rerun"
)

# Check if there's a selection
if selection is not None and selection.box:
    # Extract the datetime range from the selection
    x0, x1 = selection.box[0], selection.box[2]
    
    # Convert to datetime if they're timestamps
    start_date = pd.to_datetime(x0)
    end_date = pd.to_datetime(x1)
    
    # Create a button to store the selection
    if st.button('Store Selected Range'):
        new_selection = pd.DataFrame({
            'start_date': [start_date],
            'end_date': [end_date]
        })
        st.session_state.stored_selections = pd.concat([
            st.session_state.stored_selections,
            new_selection
        ]).reset_index(drop=True)
        st.success('Selection stored!')

# Display stored selections
if not st.session_state.stored_selections.empty:
    st.subheader('Stored Time Ranges')
    st.dataframe(st.session_state.stored_selections)