Question

我正在学习Python上的嵌套字典。我想知道如何从嵌套字典中提取特定信息。我的数据如下：

data = {
    "1": {'area': 'Administration', 'expenditure': '315'},
    "2": {'area': 'Administration', 'expenditure': '120'},
    "3": {'area': None, 'expenditure': '314'},
    "4": {'area': 'Aids and appliances', 'expenditure': None},
    "5": {'area': 'Aids and appliances', 'expenditure': '12'},
    "6": {'area': 'Administration', 'expenditure': '110'},
    "7": {'area': 'Administration', 'expenditure': '300'},
}

如何提取每个领域的所有支出信息？任何帮助表示赞赏。

Answer 1

要查找expenditure键的值：

for findvals in data.values():
   for k, v in findvals.items():
      if k == "expenditure":
         print(v)

### this prints all the values for key equal to "expenditure"

Answer 2

使用collections.defaultdict。创建一个字典，其中面积作为键，支出作为列表中的值。


from collections import defaultdict

data = {
"1": {'area': 'Administration',  'expenditure': '315'},
"2": {'area': 'Administration', 'expenditure': '120'},
"3": {'area': None, 'expenditure':'314'},
"4":{'area': 'Aids and appliances', 'expenditure': None} ,
"5":{'area': 'Aids and appliances', 'expenditure': '12'},
"6":{'area': 'Administration', 'expenditure': '110'},
"7":{'area': 'Administration', 'expenditure': '300'}
}

storage = defaultdict(list)

# defaultdict allows to define keys on fly
{storage[d['area']].append(d['expenditure']) for _, d in data.items() if d['area']}

# we have append all expenditure to all areas where the area is not None.

print(storage)

# to go back to normal dictionary with list of expenditures 
results = dict(storage)

print(results) 
# outcome: {'Administration': ['315', '120', '110', '300'], 'Aids and appliances': [None, '12']}

如果您不熟悉列表理解，则可以使用常规的for循环：

# we can re-write this:
{storage[d['area']].append(d['expenditure']) for _, d in data.items() if d['area']}

# to
for _, d in data.items():
    if d['area']:
        storage[d['area']].append(d['expenditure'])
# get all items, and add them to storage if area is not False.

为了效率，我更喜欢第一，但为了提高可读性，您可以第二。

Answer 3

尝试

[val['expenditure'] for val in data.values() if val['area'] in ['Administration', 'Aids and appliances']]

Answer 4

您将字典写错了（没有注释和错字！）

data = 
{'1': {'area': 'Administration', 'expenditure': '315'},
 '2': {'area': 'Administration', 'expenditure': '120'},
 '3': {'area': None, 'expenditure': '314'},
 '4': {'area': 'Aids and appliances', 'expenditure': None},
 '5': {'area': 'Aids and appliances', 'expenditure': '12'}}

只需执行以下操作：

[[(v.get("area", None),y) for x,y in v.items() if x=='expenditure'] for k,v in data.items()]

Answer 5

我认为您想在expenditure上使用特定的specific areas。如果您需要所有区域，则只需从我的代码中删除一个条件，否则您可以引用所有其他答案。我按照用户输入的任何区域名称来执行此操作，他将获得该特定expenditures中的area。

    def findExpense(data):
        a = input("Enter area to find expenditure : ")
        ex_dict = {}
        # create expenditure list as values to ex_dict
        ex_dict[a] = []
        for _,vals in data.items():
            if vals['area'] == a:
                ex_dict[a].append(vals['expenditure'])
        return ex_dict

    print(findExpense({
        "1": {'area': 'Administration', 'expenditure': '315'},
        "2": {'area': 'Administration', 'expenditure': '120'},
        "3": {'area': None, 'expenditure': '314'},
        "4": {'area': 'Aids and appliances', 'expenditure': None},
        "5": {'area': 'Aids and appliances', 'expenditure': '12'},
        "6": {'area': 'Administration', 'expenditure': '110'},
        "7": {'area': 'Administration', 'expenditure': '300'}
    }))

如果您熟悉list comprehension，则可以用以下代码替换for循环。

    ex_dict[a] = [vals['expenditure'] for _, vals in data.items() if vals['area'] == a]
    return ex_dict

从Python上的嵌套字典中提取所有信息

5 个答案: