列表返回 None 值而不是类对象

如何解决列表返回 None 值而不是类对象

在我的角色扮演派对创建者程序中，我试图让用户创建一个类对象，添加属性，并将其存储到派对列表索引中。然而，当玩家返回主菜单（显示派对列表的 main() 函数）时，插槽仍显示 None 值。这是我的代码：

class Creature:
    def __init__(self):
        self.name = None
        self.feet = None
        self.inches = None
        self.weight = None
        self.gender = None

    def getName(self):
        return "Name: {}".format(self.name)

    def setName(self,name):
         self.name = name

    def getHeight(self):
        return "Height: {} ft. {} in.".format(self.feet,self.inches)

    def setFeet(self,feet):
        self.feet = feet

    def setInches(self,inches):
        self.inches = inches

    def getWeight(self):
        return "Weight: {} lbs.".format(self.weight)

    def setWeight(self,weight):
        self.weight = weight

    def getGender(self):
        return "Gender: {}".format(self.gender)

    def setGender(self,index):
        genders = ['Male','Female','Others']
        if int(index) == 1:
            self.gender = genders[0]
        elif int(index) == 2:
            self.gender = genders[1]
        elif int(index) == 3:
            self.gender = genders[2]

class Dragon(Creature):
    pass

class Mermaid(Creature):
    pass

class Fairy(Creature):
    pass

class Vampire(Creature):
    pass


#allows the user to change attributes of creature
def changeAttributes(creature):
    value = input("Pick an attribute to change: 1) name   2) height   3) weight   4) gender   5) save")
    if int(value) == 1:
        creature.setName(input("Enter a name: "))
        return changeAttributes(creature)
    elif int(value) == 2:
        creature.setFeet(input("Enter a foot value: "))
        creature.setInches(input("Enter an inch value: "))
        return changeAttributes(creature)
    elif int(value) == 3:
        creature.setWeight(input("Enter a value in pounds: "))
        return changeAttributes(creature)
    elif int(value) == 4:
        creature.setGender(input("Enter a value to set gender; 1 = male,2 = female,3 = others: "))
        return changeAttributes(creature)
    elif int(value) == 5:
        confirm = input("Save?  1) yes  2) no")
        if int(confirm) == 1:
            print('Saving...')
            return menu(creature)
        else:
            return changeAttributes(creature)
    else:
        print("Not a valid input,please try again.")
        return changeAttributes(creature)

#prints the attributes of the creature
def showAttributes(creature):
    print(creature.getName())
    print(creature.getHeight())
    print(creature.getWeight())
    print(creature.getGender())
    menu(creature)

def Delete(creature):
    a = input("Are you sure?  1) yes   2) no  ")
    if int(a) == 1:
        print("Deleting...")
        creature = None
        return main()
    elif int(a) == 2:
        print("Cancelled")
        return menu(creature)

#checks to see if slot is empty or has a creature object; if empty,create a creature,otherwise go to creature menu
def menu(creature):
    value = input("Select an option  1) Show Attributes   2) Change Attributes  3) Delete   4) Back")
    if int(value) == 1:
        return showAttributes(creature)
        return menu(creature)
    elif int(value) == 2:
        return changeAttributes(creature)
        return menu(creature)
    elif int(value) == 3:
        return Delete(creature)
    elif int(value) == 4:
        return main()

#checks if slot is empty,if empty,choose a creature subclass and change attributes,else takes user directly to change attribute menu
def check(slot):
    if slot == None:
        a = input('Choose a creature: 1) Dragon   2) Fairy   3) Mermaid   4) Vampire')
        if int(a) == 1:
            slot = Dragon()
        elif int(a) == 2:
            slot = Fairy()
        elif int(a) == 3:
            slot = Mermaid()
        elif int(a) == 4:
            slot = Vampire()
        return changeAttributes(slot)
    else:
        return menu(slot)

#user select a slot; note that since development has not finished,you can only change slot 1
def main():
    global party
    print(party)
    inp = input("Select a slot: ")
    inp_1 = int(inp) - 1
    if int(inp) > 0 and int(inp) < 6:
        print("Slot {} selected!".format(int(inp)))
        return check(party[inp_1])

party = [None,None,None]

main()

到目前为止程序是这样运行的：

[None,None]
Select a slot:
#User inputs 1
Slot 1 selected!
Choose a creature: 1) Dragon   2) Fairy   3) Mermaid   4) Vampire
#User inputs 1
Pick an attribute to change: 1) name   2) height   3) weight   4) gender   5) save
#User inputs 1
Enter a name: *Name*
Pick an attribute to change: 1) name   2) height   3) weight   4) gender   5) save
#User inputs 5
Save?  1) yes  2) no
#User inputs 1
Saving...
Select an option  1) Show Attributes   2) Change Attributes  3) Delete   4) Back
#User inputs 4

然而，在你回到 main() 之后，列表仍然显示如下：

[None,None]
Select a slot: 

没有意义的是函数中的参数应该遵循最终会导致派对插槽的链式规则。我想要它，以便插槽索引将存储一个类对象而不是 None。据我所知，我可能需要使用全局变量，但在那之后我没有发现太多。有什么办法可以解决这个问题？

编辑：所以我设法解决了这个问题。我只是将 check() 函数放在 main() 中。它是这样的：

def main():
    print(party)
    inp = input("Select a slot: ")
    inp_1 = int(inp) - 1
    if int(inp) > 0 and int(inp) < 6:
        print("Slot {} selected!".format(int(inp)))
        if party[inp_1] == None:
            a = input('Choose a creature: 1) Dragon   2) Fairy   3) Mermaid   4) Vampire')
            if int(a) == 1:
                slot = Dragon()
            elif int(a) == 2:
                slot = Fairy()
            elif int(a) == 3:
                slot = Mermaid()
            elif int(a) == 4:
                slot = Vampire()
            party[inp_1] = slot
            return changeAttributes(party[inp_1])
        else:
            return menu(party[inp_1])

解决方法

main 的结尾没有“返回”的感觉。我认为您应该做的是编辑派对列表。因此代替

return check(party[inp_1])

你应该试试

party[inp_1] = check(party[inp_1])

确保检查函数返回一个生物类别，我不确定。

有一些非常奇怪的交互，你真的应该尝试为所有这些创建类和方法。在菜单功能的第四个 elseif 中，您不必再次调用 main。