Stock_Update.py

import yfinance as yf

Stock_Symbol = ""

while Stock_Symbol != "R":

    def is_valid_ticker(symbol: str) -> bool:
        """
        Checks if a ticker symbol is valid by trying to fetch recent price history.
        Returns True if data exists, False otherwise.
        """
        try:
            ticker = yf.Ticker(symbol)
            # Try to get the last 5 trading days of data
            hist = ticker.history(period="5d")
            
            # If DataFrame is empty or has no rows → likely invalid
            if hist.empty:
                return False
            
            # Optional: extra strict check — ensure we have at least one valid close price
            if hist['Close'].dropna().empty:
                return False
            
            return True
        
        except Exception as e:
            # Catches JSON decode errors, connection issues, invalid symbols, etc.
            # print(f"Validation error for {symbol}: {e}")  # optional for debugging
            return False
        


    while not Stock_Symbol:
        print("Welcome to Stock Update Tool. (To exit, enter 'R')")
        Stock_Symbol = input("Enter Stock Symbol: ").strip().upper()

        if not Stock_Symbol:
            print("Stock Symbol cannot be empty. Please try again.")
        elif not Stock_Symbol.isalnum():
            print("Stock Symbol must be alphanumeric. Please try again.")
            Stock_Symbol = ""
        elif len(Stock_Symbol) > 5:
            print("Stock Symbol must be 5 characters or fewer. Please try again.")
            Stock_Symbol = ""
        elif not is_valid_ticker(Stock_Symbol):
            print(f"'{Stock_Symbol}' is not a valid stock ticker. Please try again.")
            Stock_Symbol = ""

    def get_stock_percent_change(symbol: str) -> float:
        """
        Fetches the stock data and calculates the percentage change from open to close.
        Returns the percentage change as a float.
        """
        ticker = yf.Ticker(symbol)
        hist = ticker.history(period="1d")
        
        if hist.empty:
            raise ValueError(f"No data found for ticker '{symbol}'")
        
        open_price = hist['Open'].iat[0] 
        close_price = hist['Close'].iat[0]

        percent_change = ((close_price - open_price) / open_price) * 100
        return percent_change
    
    def news_fetcher(symbol: str, debug: bool = False):
        news = yf.Ticker(symbol).news
        if not news:
            print("No news items found.")
            return news

        from datetime import datetime

        for item in news:
            # Handle both old & new yfinance formats
            content = item.get("content") if isinstance(item.get("content"), dict) else item

            title = content.get("title")
            link = content.get("canonicalUrl", {}).get("url") or content.get("link")
            publisher = content.get("provider", {}).get("displayName") or content.get("publisher")
            published = content.get("pubDate")

            # 🔥 Skip non-articles
            if not title or not link:
                continue

            print(f"- {title}")
            print(f"  Source: {publisher or 'Unknown'}")
            if published:
                print(f"  Published: {published}")
            print(f"  Link: {link}")
            print("-" * 40)

        return news


    
    if Stock_Symbol == "R":
        print("Exiting the Stock Update Tool. Goodbye!")
        break
    else:
        Percentage_Change = get_stock_percent_change(Stock_Symbol)

        print(f"'{Stock_Symbol}' is a valid stock ticker.")
        print(f"Percentage Change from Open to Close: {Percentage_Change:.2f}%")
        print("Latest News:")
        news = news_fetcher(Stock_Symbol)

        Stock_Symbol = ""  # Reset for next iteration