KeyError(Key) 与 defaultdict 一起使用时

问题描述

当我尝试使用 defaultdict(list) 附加到字典时出现以下错误。根据我的理解，defaultdict 是为了防止 keyerror。

    raise KeyError(key) from err

键错误：'id'

以下是我的代码：

weather_data = defaultdict(list)
m = len(_ids)
date = str(date.today())
i = 0

while i < m:

url = ("https://api.openweathermap.org/data/2.5/weather?id=%s&units=%s&appid=%s") % 
(_ids.loc[i],'imperial',weather_key)
payload = r.get(url).json()
payload_from_json = pd.json_normalize(payload)

weather_data[date].append(date)
weather_data['id'].append(payload_from_json['id'])
weather_data['weather'].append(payload_from_json['weather'])
weather_data['base'].append(payload_from_json['base'])
weather_data['visibility'].append(payload_from_json['visibility'])
weather_data['dt'].append(payload_from_json['dt'])
weather_data['name'].append(payload_from_json['name'])
weather_data['cod'].append(payload_from_json['cod'])
weather_data['coord.lon'].append(payload_from_json['coord.lon'])
weather_data['coord.lat'].append(payload_from_json['coord.lat'])
weather_data['main.temp'].append(payload_from_json['main.temp'])
weather_data['main.feels_like'].append(payload_from_json['main.feels_like'])
weather_data['main.temp_min'].append(payload_from_json['main.temp_min'])
weather_data['main.temp_max'].append(payload_from_json['main.temp_max'])
weather_data['main.pressure'].append(payload_from_json['main.pressure'])
weather_data['main.humidity'].append(payload_from_json['main.humidity'])
weather_data['wind.speed'].append(payload_from_json['wind.speed'])
weather_data['wind.deg'].append(payload_from_json['wind.deg'])
weather_data['clouds.all'].append(payload_from_json['clouds.all'])
weather_data['sys.type'].append(payload_from_json['sys.type'])
weather_data['sys.id'].append(payload_from_json['sys.id'])
weather_data['sys.country'].append(payload_from_json['sys.country'])
weather_data['sys.sunrise'].append(payload_from_json['sys.sunrise'])
weather_data['sys.sunset'].append(payload_from_json['sys.sunset'])

i = i + 1

打印（天气数据）

这是回溯错误 - 有人能告诉我如何解释这个：

   Traceback (most recent call last):
  File "/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexes/base.py",line 2895,in get_loc
    return self._engine.get_loc(casted_key)
  File "pandas/_libs/index.pyx",line 70,in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/index.pyx",line 101,in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi",line 1675,in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi",line 1683,in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'coord.lon'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "main.py",line 40,in <module>
    weather_data['coord.lon'].append(payload_from_json['coord.lon'])
  File "/opt/anaconda3/lib/python3.8/site-packages/pandas/core/frame.py",line 2902,in __getitem__
    indexer = self.columns.get_loc(key)
  File "/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexes/base.py",line 2897,in get_loc
    raise KeyError(key) from err

解决方法

[编辑] 您的 weather_data 是您的默认字典，但 payload_from_json 不是。所以你的错误是由 payload_from_json 提出的。

您可以通过使用 get 访问密钥来解​​决此问题：

weather_data['id'].append(payload_from_json.get('id'))

如果不想包含垃圾数据，可以在追加前添加一些验证：

if payload_from_json.get('id') is not None:
         weather_data['id'].append(payload_from_json.get('id'))

此外，您可以添加一些默认值，如下所示：

weather_data['id'].append(payload_from_json.get('id','missing'))

或

weather_data['id'].append(payload_from_json.get('id',''))

或默认：

weather_data['id'].append(payload_from_json.get('id',None))

在您的具体问题中，这应该有效：

weather_data = defaultdict(list)
m = len(_ids)
date = str(date.today())
i = 0

while i < m:

url = ("https://api.openweathermap.org/data/2.5/weather?id=%s&units=%s&appid=%s") % 
(_ids.loc[i],'imperial',weather_key)
payload = r.get(url).json()
payload_from_json = pd.json_normalize(payload)

weather_data[date].append(date)
weather_data['id'].append(payload_from_json.get('id'))
weather_data['weather'].append(payload_from_json.get('weather'))
weather_data['base'].append(payload_from_json.get('base'))
weather_data['visibility'].append(payload_from_json.get('visibility'))
weather_data['dt'].append(payload_from_json.get('dt'))
weather_data['name'].append(payload_from_json.get('name'))
weather_data['cod'].append(payload_from_json.get('cod'))
weather_data['coord.lon'].append(payload_from_json.get('coord.lon'))
weather_data['coord.lat'].append(payload_from_json.get('coord.lat'))
weather_data['main.temp'].append(payload_from_json.get('main.temp'))
weather_data['main.feels_like'].append(payload_from_json.get('main.feels_like'))
weather_data['main.temp_min'].append(payload_from_json.get('main.temp_min'))
weather_data['main.temp_max'].append(payload_from_json.get('main.temp_max'))
weather_data['main.pressure'].append(payload_from_json.get('main.pressure'))
weather_data['main.humidity'].append(payload_from_json.get('main.humidity'))
weather_data['wind.speed'].append(payload_from_json.get('wind.speed'))
weather_data['wind.deg'].append(payload_from_json.get('wind.deg'))
weather_data['clouds.all'].append(payload_from_json.get('clouds.all'))
weather_data['sys.type'].append(payload_from_json.get('sys.type'))
weather_data['sys.id'].append(payload_from_json.get('sys.id'))
weather_data['sys.country'].append(payload_from_json.get('sys.country'))
weather_data['sys.sunrise'].append(payload_from_json.get('sys.sunrise'))
weather_data['sys.sunset'].append(payload_from_json.get('sys.sunset'))

i += 1