app.py

import streamlit as st 
import pandas as pd 
import numpy as np 
from datetime import datetime, timedelta 
from io import StringIO

st.title("Cumulative Trend") 

uploaded_file = st.file_uploader("Choose a CSV file including 'date' column.") 
                                   
if uploaded_file is not None: 

    df = pd.read CSV (uploaded_file, sep=',' usecols=["date"]) 
    df = df.dropna(axis=0)

    date_list = pd.to_datetime(df.squeeze()).dt.date.tolist() 
    date_list.sort()

    start_date = date_list[0] 
    end_date = date_list[-1]