Question

您好我有一个如下字典：

dictionary = {'John': {'car':12, 'house':10, 'boat':3},
              'Mike': {'car':5, 'house':4, 'boat':6}}

我希望获得访问权并提取子字典中的密钥，并将它们分配给这样的变量：

cars_total = dictionary['car']
house_total = dictionary['house']
boat_total = dictionary['boat']

现在，当我运行上面的变量时，我得到了一个关键错误＆＃39;。这是可以理解的，因为我需要先访问外部字典。如果有人帮助了解如何访问密钥和子字典中的值，我会很感激，因为那些是我想要使用的值。

此外，我想创建一个新密钥，这可能不对，但在这些方面的东西：

    car = dictionary['car']
    house = dictionary['house']
    boat = dictionary['boat']

dictionary['total_assets'] = car + house + boat

我希望能够访问字典中的所有密钥并创建新密钥。外键如＆＃34; John＆＃39;和迈克＆＃39;应该在最后都包含新制作的密钥。我知道这会引发错误，但它会让你知道我想要实现的目标。谢谢你的帮助

Answer 1

我只想使用Counter对象来获取总数：

>>> from collections import Counter
>>> totals = Counter()
>>> for v in dictionary.values():
...     totals.update(v)
...
>>> totals
Counter({'car': 17, 'house': 14, 'boat': 9})
>>> totals['car']
17
>>> totals['house']
14
>>>

即使钥匙始终不存在，这也可以很好地工作。

如果您想要总资产，则可以简单地将值相加：

>>> totals['total_assets'] = sum(totals.values())
>>> totals
Counter({'total_assets': 40, 'car': 17, 'house': 14, 'boat': 9})
>>>

Answer 2

汇总每个人的总资产并将其添加为新密钥：

for person in dictionary:
    dictionary[person]['total_assets'] = sum(dictionary[person].values())

将导致：

dictionary = {'John': {'car':12, 'house':10, 'boat':3, 'total_assets':25},
              'Mike': {'car':5, 'house':4, 'boat':6, 'total_assets':15}}

Answer 3

正如您所见，

dictionary没有钥匙car。但dictionary['John']确实如此。

$ >>> dictionary['John']
{'car': 12, 'boat': 3, 'house': 10}
>>> dictionary['John']['car']
12
>>>

与dictionary中的每个键相关联的值本身就是另一个字典，您可以单独编制索引。没有单个对象包含例如每个子字典的car值;你必须迭代超过每个值。

# Iterate over the dictionary once per aggregate
cars_total = sum(d['car'] for d in dictionary.values())
house_total = sum(d['house'] for d in dictionary.values())
boat_total = sum(d['boat'] for d in dictionary.values())

或

# Iterate over the dictionary once total
cars_total = 0
house_total = 0
boat_total = 0
for d in dictionary.values():
    cars_total += d['car']
    house_total += d['house']
    boat_total += d['boat']

Answer 4

dictionary = {'John': {'car':12, 'house':10, 'boat':3},'Mike': {'car':5, 'house':4, 'boat':6}}
total_cars=sum([dictionary[x]['car'] for x in dictionary ])
total_house=sum([dictionary[x]['house'] for x in dictionary ])
total_boats=sum([dictionary[x]['boat'] for x in dictionary ])
print(total_cars)
print(total_house)
print(total_boats)

Answer 5

示例迭代方法：

from collections import defaultdict
totals = defaultdict(int)
for person in dictionary:
    for element in dictionary[person]:
        totals[element] += dictionary[person][element]

print(totals)

输出：

defaultdict(<type 'int'>, {'car': 17, 'boat': 9, 'house': 14})

访问字典

5 个答案: