我在python上写了一个货币转换器，它说'；货币'；是时未定义。这发生在最后的乘法运算中

变量

money

实际上没有在

xe1

中定义，因为它的作用域仅限于

函数。在更好的实现中，您可以将money作为两个函数的参数传递，如下所示：

usd = 2
yen = 1000
gbp = 1.7
eur = 0.75

def again():
    choice = False
    while choice == False:
        money = input("please enter an amount ")
    try:
        int(money)
    except ValueError:
        print("inavlid: numbers only")
        choice == False
    else:
        money = int(money)
        if money >= 1000:
            confirm = input("are you sure y / n").lower()
            if confirm == "y":
                transfer()
            elif confirm == "n":
                again()
            elif confirm != "y" or choice != "n":
                print("invalid options")
                yn()
        else:
            transfer()
def xe1():
    xe = input("do you want currency rates set on this program(yes) or\ndo you want to make your own currency amounts(no)\n")
    if xe == 'yes':
        print ("you have got from ", (money), c, "to ", ((money)/c1*ac1),ac)
        quit()
    elif xe == 'no':
        er = (float(input("what is the exchange rate ")))
        print ("you have got from ", (money), c, "to ", ((money)*er), ac)
        quit()
    else:
        xe1()

没错，
money
没有在
xe1
中定义，也没有作为参数传递给它。我建议您阅读并遵循Python教程。有一个很好的答案应该会有所帮助。
usd = 2
yen = 1000
gbp = 1.7
eur = 0.75

def again(money):
    choice = False
    while choice == False:
        money = input("please enter an amount ")
    try:
        int(money)
    except ValueError:
        print("inavlid: numbers only")
        choice == False
    else:
        money = int(money)
        if money >= 1000:
            confirm = input("are you sure y / n").lower()
            if confirm == "y":
                transfer()
            elif confirm == "n":
                again(money)
            elif confirm != "y" or choice != "n":
                print("invalid options")
                yn()
        else:
            transfer()
def xe1(money):
    xe = input("do you want currency rates set on this program(yes) or\ndo you want to make your own currency amounts(no)\n")
    if xe == 'yes':
        print ("you have got from ", (money), c, "to ", ((money)/c1*ac1),ac)
        quit()
    elif xe == 'no':
        er = (float(input("what is the exchange rate ")))
        print ("you have got from ", (money), c, "to ", ((money)*er), ac)
        quit()
    else:
        xe1(money)