Explore Courses Blog Tutorials Interview Questions
0 votes
in Data Science by (18.4k points)

I'm trying to "execute" a (fake) buy order on a stock. I hit an error at the cash = cashcheck["cash"] line. It's saying that the indices must be integers, but we're talking about money, so it can't be int because there are decimals involved... or so I think.

Help is greatly appreciated!


@app.route("/buy", methods=["GET", "POST"])


def buy():

    """Buy shares of stock"""

    if request.method == "GET":

        return render_template("/buy.html")


        # collect user input - symbol

        symbol = request.form.get("symbol").upper()

        # if input is blank or symbol doesn't exist, return apology

        if not symbol:

            return apology("You must enter a stock symbol.", 300)

        # collect user input - # of shares

        shares = int(request.form.get("shares"))

        # if blank or not a positive integer, return apology

        if not shares:

            return apology("Enter a valid number of shares.", 300)

        # pull current price info from API

        quote = lookup(symbol)

        shareprice = quote["price"]

        totalprice = shareprice * shares

        # check users table to see how much cash user has

        cashcheck = db.execute("SELECT cash FROM users WHERE id = :userid", userid = session["user_id"])

        cash = cashcheck["cash"]

        if cash >= totalprice:

            # in transactions table, insert userID, symbol, shares, shareprice, and totalprice

            # transID should be autogenerated and autoincremented.  date is also autofilled by SQLite.

            db.execute("INSERT INTO transactions (userID, symbol, shares, shareprice, totalprice) VALUES (:userid, :symbol, :shares, :shareprice, :totalprice)",

            userid=session["user_id"], symbol=symbol, shares=shares, shareprice=shareprice, totalprice=totalprice)

            cash = cash - totalprice

            # update cash balance

            db.execute("UPDATE users SET cash = :cash WHERE id = :userid", userid = session["user_id"])

            #return index

            return ("/")


            # else, return apology (not enough cash)

            return apology("Not enough cash balance to make execute this order.", 300)


ERROR:application:Exception on /buy [POST]

Traceback (most recent call last):

  File "/usr/local/lib/python3.7/site-packages/flask/", line 2446, in wsgi_app

    response = self.full_dispatch_request()

  File "/usr/local/lib/python3.7/site-packages/flask/", line 1951, in full_dispatch_request

    rv = self.handle_user_exception(e)

  File "/usr/local/lib/python3.7/site-packages/flask/", line 1820, in handle_user_exception

    reraise(exc_type, exc_value, tb)

  File "/usr/local/lib/python3.7/site-packages/flask/", line 39, in reraise

    raise value

  File "/usr/local/lib/python3.7/site-packages/flask/", line 1949, in full_dispatch_request

    rv = self.dispatch_request()

  File "/usr/local/lib/python3.7/site-packages/flask/", line 1935, in dispatch_request

    return self.view_functions[rule.endpoint](**req.view_args)

  File "/home/ubuntu/finance/", line 34, in decorated_function

    return f(*args, **kwargs)

  File "/home/ubuntu/finance/", line 86, in buy

    if cashcheck["cash"] >= totalprice:

TypeError: list indices must be integers or slices, not str

1 Answer

0 votes
by (36.8k points)
edited by

cash check is a list of rows that matched the query.

If you're only expecting one row to match, use cashcheck[0]["cash"].

Learn Data Science with Python Course to improve your technical knowledge.

Welcome to Intellipaat Community. Get your technical queries answered by top developers!

29.3k questions

30.6k answers


104k users

Browse Categories