How to condition a variable by calling the value?

Question

I have a doubt. Previously I made my first Python program with everything I learned, it was about the system of a vending machine, but one of the main problems was that it was too redundant when conditioning and ended up lengthening the code. So they explained to me that I should define the functions and return in case they are not fulfilled.

But my question is, how can I call the value of a variable, specifically a number, by conditioning it?

Example:

# -*- coding: utf-8 -*-


def select_ware(wares):
    print(' '.join(wares))
    while True:
        selected = input("Elige un código: ")
        if selected in wares:
            print(f'El precio es de: {wares[selected]}\n')
            break
        else:
            print("El código no existe, introduce un código válido")
    return selected

def pay_ware(wares, selected):
    money_needed = wares[selected]
    money_paid = 0
    while money_paid < money_needed:
        while True:
            try:
                money_current = float(input("Introduce tu moneda: "))
                break
            except ValueError:
                print('Please enter a number.')

        money_paid += money_current
        print(f'Paid ${money_paid}/${money_needed}')

        if money_paid>{select_ware}: #This is the part where I want to substitute the value to call the variable.
            print(f'Su cambio es ${money_paid-money_needed}')        
        
    return money_paid, money_needed

def main():
    wares = {'A1': 6, 'A2': 7.5, 'A3': 8, 'A4': 10, 'A5': 11}

    selected_ware = select_ware(wares)
    pay_ware(wares, selected_ware)


if __name__ == "__main__":
    main()

The question is this:

if money_paid>{select_ware}: #This is the part where I want to substitute the value to call the variable.
    print(f'Su cambio es ${money_paid-money_needed}')  

How can I implement it to avoid making long conditions for each value, that is, for the value of 'A1': 6, 'A2': 7.5, 'A3': 8, 'A4': 10, 'A5': 11? Thanks for reading. Regards.

Answer 1

You are almost done! Just modify {select where} by money needed. You can also modify the Try Exception statement in order to avoid stop your program until the money current is a float number:

def pay_ware(wares, selected):
    money_needed = wares[selected]
    money_paid = 0
    valid_money_current = False # para chequear que el pago sea con monedas
    while money_paid < money_needed:
        while not valid_money_current:
                money_current = float(input("Introduce tu dinero: "))
                if type(money_current) is float:
                    valid_money_current = True # el pago es valido
                else:
                    print('Please enter a number.')

        money_paid += money_current
        print(f'Paid ${money_paid}/${money_needed}')

        if money_paid > money_needed: #This is the part where I want to substitute the value to call the variable.
            print(f'Su cambio es ${money_paid-money_needed}')        
        
    return money_paid, money_needed