Question

我正在尝试使用for循环从json中提取有关几个城市天气模式的数据，并将所述数据输入到数据框df_cities中：

units = 'imperial'
params = {'appid': api_key,
         'units': units}

for index, row in df_cities.iterrows():    
    base_url = "http://api.openweathermap.org/data/2.5/weather?"
    city = row['Name']
    params['q'] = f'{city}'
    response = requests.get(base_url, params=params).json()

    df_cities.loc[index, 'Temperature'] = response['main']['temp']
    df_cities.loc[index, 'Humidity'] = response['main']['humidity']
    df_cities.loc[index, 'Cloudiness'] = response['main']['temp']
    df_cities.loc[index, 'Windspeed'] = response['wind']['speed']

但是，无论我以何种方式构造循环，我都会不断收到KeyError：'main'。但是，如果我在循环外执行response ['main] ['temp']，则会得到所需的结果：

citys = 'Chicago'
units = 'imperial'
url = "http://api.openweathermap.org/data/2.5/weather?"
query_url = f'{url}appid={api_key}&q={citys}&units={units}'
response = requests.get(query_url).json()

response['main']['temp']

39.33

为什么python无法在循环中识别json？

Answer 1

Chicago的响应确实包含df_cities.iterrows()键，但是在某个时候，您的main循环会在其他城市中产生一个没有main键的城市。

您可以在尝试访问if 'main' in response: df_cities.loc[index, 'Temperature'] = response['main']['temp'] df_cities.loc[index, 'Humidity'] = response['main']['humidity'] df_cities.loc[index, 'Cloudiness'] = response['main']['temp'] df_cities.loc[index, 'Windspeed'] = response['wind']['speed'] else: print('main key not in response JSON for city %s' % city)之前检查其是否存在：

{{1}}

尽管代码在其他地方工作，但仍然不断收到KeyError：'main'

1 个答案: