返回 NonType 的 Python 子例程

Question

所以我用 python 创建了这个水果机，当我调用变量来检查机器的结果时，子例程返回一个非类型错误

我尝试用几种方法将返回的变量强制转换为浮点数（我需要它是什么），但没有成功 我不知道还能尝试什么：我浏览了很多网站并向朋友寻求帮助，但都没有成功；我尝试重写函数的调用方式但没有改变；返回函数如何返回奖金变量，但注意事项已更改。我复制了下面的代码。

import random
money = 1.00
finish = False


print (" You have £", money)

def prizecheck(tocheck,winnings):
    if wheel1 == tocheck:
        if wheel2 == tocheck:
            if wheel3 == tocheck:
                if tocheck == "Skull":
                    winnings = 0
                    return winnings
                    print ("The house wins, All money lost")
                elif tocheck == "Cherry" or tocheck == "Lemon" or tocheck == "Orange" or tocheck == "Star":
                    print ("You win £1")
                    winnings = winnings + 1
                    return winnings
                elif tocheck == "Bell":
                    print ("You win £5")
                    winnings = winnings + 5
                    return winnings
            else:
                if tocheck == "Skull":
                    winnings = winnings - 1.00
                    return winnings
                elif tocheck == "Cherry" or tocheck == "Lemon" or tocheck == "Orange" or tocheck == "Star" or tocheck == "Bell":
                    print ("You win 50p")
                    winnings = winnings + 0.50
                    return winnings
        elif wheel3 == tocheck:
            if tocheck == "Skull":
                print ("The house wins, you lost £1")
                winnings = winnings - 1.00
                return winnings
            elif tocheck == "Cherry" or tocheck == "Lemon" or tocheck == "Orange" or tocheck == "Star" or tocheck == "Bell":
                print ("You win 50p")
                winnings = winnings + 0.50
                return winnings
    elif wheel2 == tocheck:
        if wheel3 == tocheck:
            if tocheck == "Skull":
                print ("The house wins, you lost £1")
                winnings = winnings - 1.00
                return winnings
            elif tocheck == "Cherry" or tocheck == "Lemon" or tocheck == "Orange" or tocheck == "Star" or tocheck == "Bell":
                print ("You win 50p")
                winnings = winnings + 0.50
                return winnings
            
def spin():
    picture = random.randint(1,6)
    if picture == 1:
        wheel = "Cherry"
    elif picture == 2:
        wheel = "Bell"
    elif picture == 3:
        wheel = "Lemon"
    elif picture == 4:
        wheel = "Orange"
    elif picture == 5:
        wheel = "Star"
    else:
        wheel = "Skull"
    return wheel

    


while money >= 0.2 and finish != True:
    money = money - 0.2
    wheel1 = spin()
    wheel2 = spin()
    wheel3 = spin()
    print(wheel1,"|",wheel2,"|",wheel3)
    
    change = prizecheck("Skull",money)
    change = prizecheck("Cherry",money)
    change = prizecheck("Bell",money)
    change = prizecheck("Lemon",money)
    change = prizecheck("Orange",money)
    change = prizecheck("Star",money)
    
    money = change
    
    print("You have £",money)
    
    endcheck = input("Spin again (1), or quit(2)?")
    if endcheck == "2":
        finish = True
    
    if money < 0.20:
        print("Sorry You have ran out of money")

如有任何帮助，我们将不胜感激

Answer 1

您的逻辑到达

prizecheck()

的末尾而不返回任何内容，将

winnings

设置为

None

。

尝试在那里放置调试语句，看看何时会发生这种情况。

每次更改时尝试打印

change

的值，以便可以看到图案。

养成在期望返回值的函数末尾始终添加

return

的习惯。

Python 不是静态类型语言，因此您不能强制值是浮点数。如果可以（用另一种语言），您必须指定函数的返回类型，并在此过程中出现编译器错误。您可以提供类型提示来检查此类错误，但 Python 变量始终可以设置为

None

。