在pickle字典中检索单个对象的问题（Python 3）

Question

我的程序存储“食物”对象，这些对象被腌制到字典中并存储在充当数据库的 csv 文件中。 我想根据命令从字典中检索单个食物对象，但是当我尝试时，我似乎只检索字典中的最后一个对象。

import pickle

class Food(object):
  fooddict = dict({})

  def __init__(self, name, weight, calories, time):
    self.name = name
    self.weight = weight
    self.calories = calories
    self.time = time

  def __str__(self):
    return '{self.name}s'.format(self=self) + \
           ' weigh {self.weight}'.format(self=self) + \
           ' ounces, contain {self.calories}'.format(self=self) + \
           ' calories, and stay fresh for {self.time}'.format(self=self) + \
           ' days.'

  @classmethod
  def createFoodInput(cls):
    name = str(input("Enter the name: "))
    weight = float(input("Enter the weight: "))
    calories = float(input("Enter the calories: "))
    time = float(input("Enter how many days it can store for: "))
    return cls(name, weight, calories, time)

  def storeFoodDict(f):
    fooddict = Food.retreiveFoodDict()
    if fooddict == "Empty File":
        fooddict = dict({f.name: f})
        with open("food.csv", 'wb') as filewriter:
            try:
                pickle.dump(fooddict, filewriter)
            except:
                print("Error storing pickled dictionary")
    else:
        food_found = False
        for key in list(fooddict):
            if key.__eq__(f.name):
                print("Food already stored!")
                food_found = True
        if not food_found:
            fooddict.update({f.name: f})
            with open("food.csv", 'wb') as filewriter:
                try:
                    pickle.dump(fooddict, filewriter)
                except:
                    print("Error storing pickled dictionary")
  @classmethod
  def retreiveFoodDict(cls):
    with open("food.csv", 'rb') as filereader:
        try:
            fooddict = pickle.load(filereader)
            return fooddict
        except EOFError:
            return("Empty File")

def findFood(title):
fooddict = Food.retreiveFoodDict()
for key in list(fooddict):
   if key.__eq__(title):
        continue
return fooddict[key]

s = "apple"
n = findFood(s)           #does not work, it returns banana instead of apple
                          #which is really just grabbing whatever is the 
                          #last object in the dictionary

m = findFood("banana")    #seems to work, but only because banana is the
                          #last object in the dictionary

print(n) #should print an apple "food object" but instead prints a banana

print(str(m.calories)) #works, but if I said n.calories it would still print
                       #m.calories instead
p = Food.retreiveFoodDict() #seems to work and retrieve the dictionary
print(str(p))               #also seems to work of course

控制台输出：香蕉重 5.0 盎司，含有 120.0 卡路里，可保鲜 3.0 天。
120.0
{'apple': < main .Food object at 0x00D2C2E0>, 'banana': < main .Food object at 0x00D36D00>}

字典包含 2 个食物对象（苹果和香蕉），但 print(n) 语句显示的是香蕉，而不是苹果。 谁能指出这是为什么或我误解了什么？ 非常感谢！

Answer 1

我找到了我自己问题的答案。 我在 findFood 函数中滥用了 continue。 这段代码解决了我的问题。

def getFood(food_name):
    fooddict = Food.retreiveFoodDict()
        for key in list(fooddict):
           if key.__eq__(food_name):
               return fooddict[key]

此函数所做的只是检索 csv 文件中的对象字典，并遍历键直到找到传递的键名。 如果找到，正确的键名将作为食物对象返回。 我最初的错误是使用“continue”关键字来停止 for 循环，它在我们想要的对象之后直接返回对象。