遞回函式嵌套字典python

我需要呼叫一個遞回函式來在單獨的行上像這樣列印嵌套字典的內容：

lunch : {"sandwich": 2, "chips": 1, "drink": 1}

dinner : {"ribs": 6, "mac_cheese": 1, "roll": 1, "pie": 1}

我嘗試了以下代碼，但它只是迭代嵌套字典的鍵

# recursive function for printing out meal plans 
def print_meals(meal_plan):
    for key, value in meal_plan.items():
        if type(value) is dict:
            print_meals(value)
        else:
            print(key, ":", value)

    # create an empty dictionary
    meal_plan = {}

    # create individual dictionaries for each meal
    lunch = {"sandwich": 2, "chips": 1, "drink": 1}
    dinner = {"ribs": 6, "mac_cheese": 1, "roll": 1, "pie": 1}

    #create a nested dictionary
    meal_plan["lunch"] = lunch 
    meal_plan["dinner"] = dinner 

    # call recursive function 'print_meals'
    print_meals(meal_plan)

uj5u.com熱心網友回復：

你可以在function下面定義你的喜歡：

>>> def print_meals(dct):
...    for k,v in dct.items():
...        print(f'{k} : {v}');print()

輸出：

>>> meal_plan
{'lunch': {'sandwich': 2, 'chips': 1, 'drink': 1},
 'dinner': {'ribs': 6, 'mac_cheese': 1, 'roll': 1, 'pie': 1}}

>>> print_meals(meal_plan)
lunch : {'sandwich': 2, 'chips': 1, 'drink': 1}

dinner : {'ribs': 6, 'mac_cheese': 1, 'roll': 1, 'pie': 1}

uj5u.com熱心網友回復：

這是一個想法：

def print_meals(meal_plan, depth=0):
    if isinstance(meal_plan, dict):
        for k, v in meal_plan.items():
            print('  '*depth, k, ':')
            print_meals(v, depth 1)
    else:
        print('  '*depth, meal_plan)

print_meals('sandwich')
#  sandwich

print_meals({'sandwich': 1})
#  sandwich :
#    1

print_meals({'lunch': {'sandwich': 2, 'chips': 1, 'drink': 1}, 'dinner': {'ribs': 6, 'mac_cheese': 1, 'roll': 1, 'pie': 1}})
#  lunch :
#    sandwich :
#      2
#    chips :
#      1
#    drink :
#      1
#  dinner :
#    ribs :
#      6
#    mac_cheese :
#      1
#    roll :
#      1
#    pie :
#      1

print_meals({'monday': {'lunch': {'sandwich': 1, 'apple': 2}, 'dinner': {'soup': 1, 'yaourt': 1}}, 'tuesday': {'breakfast': 'pain au chocolat', 'lunch': {'salad': 2, 'lasagna': 1}, 'dinner': {'beans':3}}})
#  monday :
#    lunch :
#      sandwich :
#        1
#      apple :
#        2
#    dinner :
#      soup :
#        1
#      yaourt :
#        1
#  tuesday :
#    breakfast :
#      pain au chocolat
#    lunch :
#      salad :
#        2
#      lasagna :
#        1
#    dinner :
#      beans :
#        3

或者，為了減少換行，但假設用餐計劃是一個字典：

def print_meals(meal_plan, depth=0):
  for k,v in meal_plan.items():
    if isinstance(v, dict):
      print('  '*depth, k, ':')
      print_meals(v, depth 1)
    else:
      print('  '*depth, k, ':', v)

print_meals({'sandwich': 1})
#  sandwich : 1

print_meals({'lunch': {'sandwich': 2, 'chips': 1, 'drink': 1}, 'dinner': {'ribs': 6, 'mac_cheese': 1, 'roll': 1, 'pie': 1}})
#  lunch :
#    sandwich : 2
#    chips : 1
#    drink : 1
#  dinner :
#    ribs : 6
#    mac_cheese : 1
#    roll : 1
#    pie : 1

print_meals({'monday': {'lunch': {'sandwich': 1, 'apple': 2}, 'dinner': {'soup': 1, 'yaourt': 1}}, 'tuesday': {'breakfast': 'pain au chocolat', 'lunch': {'salad': 2, 'lasagna': 1}, 'dinner': {'beans':3}}})
#  monday :
#    lunch :
#      sandwich : 1
#      apple : 2
#    dinner :
#      soup : 1
#      yaourt : 1
#  tuesday :
#    breakfast : pain au chocolat
#    lunch :
#      salad : 2
#      lasagna : 1
#    dinner :
#      beans : 3

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