调用之前引用局部变量。

Question

我收到的错误是UnboundLocalError:赋值前引用的局部变量'this_mammal‘

我已经练习了几天了，但这让我很困惑。我四处寻找凹痕，到处都有this_mammal，但似乎没什么问题。我不能包括哺乳动物超类和动物子类，因为我没有足够的文本来包含所有的代码。如果有必要的话，请让我知道！我可以试试。

def select_which_mammal():
    print("Welcome to the Mammal Inventory Management System!")
    print()
    print("1. Cow")
    print("2. Cat")
    print("3. Dog")
    print("4. Human")
    print("5. Platypus")
    print("6. Echidna")
    print("7. Bat")
    print()
    selection = int(input("Enter the number for the mammal you would like to add:"))

    while selection < 1 or selection > 7:
        print("ERROR: Selections must be 1-7.")
        selection = int(input("Enter the number for the mammal you would like to add:"))

def create_the_mammal(mammal_type):
    
    if mammal_type == 1: this_mammal = Mammal('Cow', 4, 3)
    
    elif mammal_type == 2: this_mammal = Mammal('Cat', 4, 9)

    elif mammal_type == 3: this_mammal = Mammal('Dog', 4, 6)

    elif mammal_type == 4: this_mammal = mammal("Human", 2, 14)
    
    elif mammal_type == 5: this_mammal = mammal("Platypus", 4, 3)

    elif mammal_type == 6: this_mammal = mammal("Echidna", 4, 3)

    elif mammal_type == 7: this_mammal = mammal("Bat", 2, 1)

    print("\nYour", this_mammal.get_name(), "has been added to the system.\n")
    
    return this_mammal

def choose_an_action(this_mammal): 
    print("Next, please choose an action for your ", this_mammal.get_name() + ".")
    print()
    print("1. Display the mammal's status")
    print("2. Hear the mammal's sound")
    print("3. Go out for a walk with your mammal")
    print("4. Breed your mammal")
    print()
    action = int(input("Enter the number for the action:"))

    while action < 1 or action > 4:
        print("ERROR: Selections must be 1-4.")
        action = input(int("Enter the number for the action:"))

    if action == 1: this_mammal.show_self()

    elif action == 2: this_mammal.make_sound()

    elif action == 3: this_mammal.ambulate()

    elif action == 4: this_mammal.reproduce()

def main():

    new_mammal = select_which_mammal()

    this_mammal = create_the_mammal(new_mammal)

    choose_an_action(this_mammal)

main()

Answer 1

您必须在return selection函数的末尾进行select_which_mammal。