Question

我是Python 2的新手。我正在尝试构建一个“购物车”Python程序，但坚持“在购买之前检查库存”步骤。

首先，我在这里阅读了许多相同问题的主题，但它们似乎与我的原因不同。

其次，我已经将每个函数分开并在另一个文件中进行测试。他们个人工作得很好。但是当加入def check_stock(y): #// Problem in this function // if y in list: print "%s is available" % y add_to_cart(y) else: print "Sorry, but %s is not available." % y def check_finish(): y = raw_input(">") if y == "checkcart": print cart #check inside shopping cart elif y == " ": check_finish() #loop back for blank elif y == "list": list() #present the list else: while y != "ok": #"ok" = finished shopping check_stock(y) else: print "Checking out..." sorted(cart) print "Your item(s) are %s." % cart exit(0)函数时，它会给出错误。

我认为问题来自于“in”命令。

cart = []
list = ['apple', 'banana', 'cat', 'dog', 'elephant', 'flamingo', 'goofy', 'ham']
a = 0

def list():
    print list                  #present the list
def representInt(s):            #check if value is integer
    try:
        int(s)
        return True
    except ValueError:
        return False
def annoyedAtError(a):          #interaction for repeated mistakes
    if a < 2:
        print "Numbers only please"
    elif 2 < a < 4:
        print "Man, just do as I say, please. I have another shift tonight."
    elif a == 5 :
        print "Hey, seriously?"
    else:
        print "..."
def check_stock(y):             #// PROBLEM HERE // cross-check with list if item is available
    if y in list:
        print "%s is available" % y
        add_to_cart(y)
    else:
        print "Sorry, but %s is not available." % y

def add_to_cart(y):
    amount = (raw_input("How many do you want to add? > "))
    if representInt(amount) == False:
        annoyedAtError(a)
        global a 
        a = a + 1
        add_to_cart(y)
    else: 
        y = y + " " + amount
        print "%s is added to cart" % (y)
        cart.append(y)
        check_finish()
def check_finish():
    y = raw_input(">")
    if y == "checkcart":        
        print cart              #check inside shopping cart
    elif y == " ":
        check_finish()          #loop back for blank
    elif y == "list":
        list()                  #present the list
    else:
        while y != "ok":        #"ok" = finished shopping
            check_stock(y)
        else:
            print "Checking out..."
            sorted(cart)
            print "Your item(s) are %s." % cart
            exit(0)
def welcome():      
    print """\nWelcome to cyber shopping.\n 
    Please enter things you want to buy.
    Check your cart by typing: checkcart
    type "ok" when finished.
    type "list" for things available for buying"""
def start():
    welcome()
    check_finish()

start()

以下是代码的其余部分，如果有帮助的话：

Email[i]+=i;

Answer 1

您创建了一个名为list的列表（您不应该这样做，因为它已经是内置名称），但是您还创建了一个名为list的函数（同样，不要这样做）这个）。 list现在指的是功能，而不是您的列表。因此，当您检查y in list时，它会尝试检查项目是否在函数中。您不能在函数上使用in，因此会出错。解决方案很简单：为事物使用更清晰的名称!!

Answer 2

lst = ['apple', 'banana', 'cat', 'dog', 'elephant', 'flamingo', 'goofy', 'ham']
a = 0

list是python中的预定义函数，因此请使用其他名称。

Answer 3

首先，不要为列表list命名！其次，功能名称越具描述性越好。所以这里有一些编辑了名称的代码：

cart = []
groceries = ['apple', 'banana', 'cat', 'dog', 'elephant', 'flamingo', 'goofy', 'ham']
a = 0

def prntgroceries():
    print groceries                  #present the groceries
def representInt(s):            #check if value is integer
    try:
        int(s)
        return True
    except ValueError:
        return False
def annoyedAtError(a):          #interaction for repeated mistakes
    if a < 2:
        print "Numbers only please"
    elif 2 < a < 4:
        print "Man, just do as I say, please. I have another shift tonight."
    elif a == 5 :
        print "Hey, seriously?"
    else:
        print "..."
def check_stock(y):             #// PROBLEM HERE // cross-check with list if item is available
    if y in groceries:
        print "%s is available" % y
        add_to_cart(y)
    else:
        print "Sorry, but %s is not available." % y

def add_to_cart(y):
    amount = (raw_input("How many do you want to add? > "))
    if representInt(amount) == False:
        annoyedAtError(a)
        global a 
        a = a + 1
        add_to_cart(y)
    else: 
        y = y + " " + amount
        print "%s is added to cart" % (y)
        cart.append(y)
        check_finish()
def check_finish():
    y = raw_input(">")
    if y == "checkcart":        
        print cart              #check inside shopping cart
    elif y == " ":
        check_finish()          #loop back for blank
    elif y == "list":
        prntgroceries()                  #present the list of groceries
    else:
        while y != "ok":        #"ok" = finished shopping
            check_stock(y)
        else:
            print "Checking out..."
            sorted(cart)
            print "Your item(s) are %s." % cart
            exit(0)
def welcome():      
    print """\nWelcome to cyber shopping.\n 
    Please enter things you want to buy.
    Check your cart by typing: checkcart
    type "ok" when finished.
    type "list" for things available for buying"""
def start():
    welcome()
    check_finish()

start()

第二件事，与您的问题无关：当您要求购买的东西时，它会打印清单......并结束程序。我建议做一些事情来阻止程序在打印可用内容列表后立即结束。也许甚至可以在最开始打印该列表。

希望这有帮助！

：TypeError：'function'类型的参数不可迭代“，但在单独测试时有效

3 个答案: