Python 购物清单程序未显示袋子类型

Question

这件事让我抓狂。在get_paper_or_plastic函数中的“请选择纸张或塑料”中提供“纸张”或“塑料”后，我不明白为什么我的程序不显示袋子类型。这是我的密码：

maximum_number_of_groceries = 500

def get_string(prompt):
    value = ""

    value = input(prompt)
    return value

def valid_real(value):
    try:
        float(value)
        return True
    except:
        return False

def get_real(prompt):
    value = ""

    value = input(prompt)
    while not valid_real(value):
        print(value, "is not a number. Please provide a number.")
        value = input(prompt)
    return float(value)


def get_paper_or_plastic(prompt):
    value = ""

    value = input(prompt)
    if value == "plastic" or value == "Plastic" or value == "paper" or value == "Paper":
        return value
    else:
        print("That is not a valid bag type. Please choose paper or plastic")
        value = input(prompt)

def y_or_n(prompt):
    value = ""

    value = input(prompt)
    while True:
        if value == "Y" or value == "y":
            return False
        elif value == "N" or value == "n":
            return True
        else:
            print("Not a valid input. Please type Y or N")
            value = input(prompt)

def get_groceries(grocery_name, quantity,paper_or_plastic):
    done = False
    counter = 0
    while not done:
        grocery_name[counter] = get_string("What grocery do you need today? ")
        quantity[counter] = get_real("How much of that item do you need today?")
        counter = counter + 1
        done = y_or_n("Do you need anymore groceries (Y/N)?")
    paper_or_plastic = get_paper_or_plastic("Do you want your groceries bagged in paper or plastic bags today?")
    return counter

def calculate_total_groceries(quantity):
    counter = 0
    total_quantity = 0

    while counter < len(quantity):
        total_quantity = total_quantity + int(quantity[counter])
        counter = counter + 1
    return total_quantity

def grocery_list():
    grocery_name = ["" for x in range (maximum_number_of_groceries)]
    quantity = [0.0 for x in range (maximum_number_of_groceries)]
    total_quantity = 0
    paper_or_plastic = ""
    get_groceries(grocery_name, quantity, paper_or_plastic)
    total_quantity = calculate_total_groceries(quantity)


    print ("Total number of groceries purchased is: ", total_quantity," and you have chosen a bag type of ", paper_or_plastic)

grocery_list()

Answer 1

如果“display”的意思是“print”，那么程序不打印行李类型的原因很简单：没有以行李类型作为参数调用print函数的实例。退货不会导致打印

顺便说一句，value == "plastic" or value == "Plastic" or value == "paper" or value == "Paper"可以替换为value.lower() in ['plastic','paper']