相同的列表/字典在多個功能

我是新來的python，目前仍在學習hwo處理列表和字典。相同的列表/字典在多個功能

我有這兩個功能

def food_database(item_name, size_serv, calorie_serv, protein_serv, carb_serv, fat_serv): 
     # used to list the different foods when users ask for it 
     # food database 
     food_dict = [ { 
     'food_name': item_name, 
     'serving_size': size_serv, 
     'serving_calorie': calorie_serv, 
     'serving_protien': protein_serv, 
     'serving_fat': fat_serv, 
     'serving_carb': carb_serv 
     } ] 
     print food_dict 

    def food_in_diet(item_name, size_serv, calorie_serv, protein_serv, carb_serv, fat_serv, num_serv): 
     # used to show how much is in the diet plan for the user 
     User_diet_dict = [ { 
     'food_name': item_name, 
     'amount': num_serv*size_serv, 
     'serving_calorie': num_serv*calorie_serv, 
     'serving_protien': protein_serv, 
     'serving_fat': fat_serv, 
     'serving_carb': carb_serv 
     } ] 
     print User_diet_dict

我有這等功能

def add_food(): 
     ask_to_add_another = raw_input("Would you like to add another food?(y/n)") 
     if ask_to_add_another == 'y': 
     # update 
     item_name = raw_input("What is the name of the food you would like to add? ") 
     size_serv = input("What is the size(grams) in each serving of %s? " % item_name) 
     calorie_serv = input("How many calories is in each serving of %s? " % item_name) 
     protein_serv = input("How many grams of protein is in each serving of %s? " % item_name) 
     carb_serv = input("How many grams of carbohydrates is in each serving of %s? " % item_name) 
     fat_serv = input("How many grams of fat is in each serving of %s? " % item_name) 
     num_serv = input("How many servings of %s would you like to add? " % item_name) 

     food_dict.append({ 
      'food_name': 'item_name', 
      'serving_size': size_serv, 
      'serving_calorie': calorie_serv, 
      'serving_protien': protein_serv, 
      'serving_fat': fat_erv, 
      'serving_carb': carb_serv 
     }) 

    # User_diet_dict.append = ({ 
    #  'food_name': item_name, 
    #  'amount': num_serv*size_serv, 
    #  'serving_calorie': num_serv*calorie_serv, 
    #  'serving_protien': protein_serv, 
    #  'serving_fat': fat_serv, 
    #  'serving_carb': carb_serv 
    # }) 
     # add to the dictonary/list 
     print food_dict 
     add_food() 
     if ask_to_add_another == 'n': 
     return False

的add_food（）函數更新food_dict字典，並添加到列表中。

我得到的錯誤

Traceback (most recent call last): 
     File "MACROCALC.py", line 156, in <module> 
     main() 
     File "MACROCALC.py", line 35, in main 
     add_food() 
     File "MACROCALC.py", line 130, in add_food 
     food_dict.append({ 
    NameError: global name 'food_dict' is not defined

我覺得好像是因爲字典是不是全球性的，這正在發生。

這裏是我的代碼，如果有人想了解 - >http://pastebin.com/mc8S6fkS

開放的建議！ Noob程序員希望變得更好！

感謝您的幫助！

來源

2013-06-22 Liondancer

這是因爲'add_food'範圍內不存在'food_dict'。解決這個問題的一種方法是使其成爲全局的，但更好的方法是將這些'print'改成'return's，調用'food_database'，並將其輸出存儲在一個變量中。 – Blender

在將變異是列表中的每個函數的頂部聲明food_dict爲global。對於list mutate基本上是分配的，而不是使用append()。通常，使用類的方法並不構成我在上面描述的意義上的變異。見下：

def init(): 
    global food_dict 
    # assignment is manipulation 
    food_dict = [{'name': 'apple'}, {'name': 'orange'}] 

def next(): 
    # notice no 'global' usage but this still works 
    food_dict.append({'name': 'kiwi'}) 

def lastly(): 
    global food_dict 
    # assign to empty list 
    food_dict = [{}] 

>>> init() 
>>> print food_dict 
[{'name': 'apple'}, {'name': 'orange'}] 
>>> next() 
>>> print food_dict 
[{'name': 'apple'}, {'name': 'orange'}, {'name': 'kiwi'}] 
>>> lastly() 
>>> print food_dict 
[{}]

來源

2013-06-22 07:21:45

添加下面的每個子routine-

global food_dict

來源

2013-06-22 02:22:59 deeshank

相同的列表/字典在多個功能

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