Question

我有一个从JSON文档创建的字典：

{
  "response": {
  "version":"0.1",
  "termsofService":"http://www.wunderground.com/weather/api/d/terms.html",
  "features": {
  "hourly": 1
  }
    }
    ,
"hourly_forecast": [
    {
    "FCTTIME": {
    "hour": "22","hour_padded": "22","min": "00","min_unpadded": "0","sec": "0","year": "2017","mon": "3","mon_padded": "03","mon_abbrev": "Mar","mday": "8","mday_padded": "08","yday": "66","isdst": "0","epoch": "1489028400","pretty": "10:00 PM EST on March 08, 2017","civil": "10:00 PM","month_name": "March","month_name_abbrev": "Mar","weekday_name": "Wednesday","weekday_name_night": "Wednesday Night","weekday_name_abbrev": "Wed","weekday_name_unlang": "Wednesday","weekday_name_night_unlang": "Wednesday Night","ampm": "PM","tz": "","age": "","UTCDATE": ""
    },
    "temp": {"english": "50", "metric": "10"},
    "dewpoint": {"english": "20", "metric": "-7"},
    "condition": "Partly Cloudy",
    "icon": "partlycloudy",
    "icon_url":"http://icons.wxug.com/i/c/k/nt_partlycloudy.gif",
    "fctcode": "2",
    "sky": "6",
    "wspd": {"english": "29", "metric": "47"},
    "wdir": {"dir": "W", "degrees": "262"},
    "wx": "Clear/Wind",
    "uvi": "0",
    "humidity": "30",
    "windchill": {"english": "-9999", "metric": "-9999"},
    "heatindex": {"english": "-9999", "metric": "-9999"},
    "feelslike": {"english": "50", "metric": "10"},
    "qpf": {"english": "0.0", "metric": "0"},
    "snow": {"english": "0.0", "metric": "0"},
    "pop": "0",
    "mslp": {"english": "30.01", "metric": "1016"}
    }
    ,
    {
    "FCTTIME": {
    "hour": "23","hour_padded": "23","min": "00","min_unpadded": "0","sec": "0","year": "2017","mon": "3","mon_padded": "03","mon_abbrev": "Mar","mday": "8","mday_padded": "08","yday": "66","isdst": "0","epoch": "1489032000","pretty": "11:00 PM EST on March 08, 2017","civil": "11:00 PM","month_name": "March","month_name_abbrev": "Mar","weekday_name": "Wednesday","weekday_name_night": "Wednesday Night","weekday_name_abbrev": "Wed","weekday_name_unlang": "Wednesday","weekday_name_night_unlang": "Wednesday Night","ampm": "PM","tz": "","age": "","UTCDATE": ""
    },
    "temp": {"english": "49", "metric": "9"},
    "dewpoint": {"english": "20", "metric": "-7"},
    "condition": "Partly Cloudy",
    "icon": "partlycloudy",
    "icon_url":"http://icons.wxug.com/i/c/k/nt_partlycloudy.gif",
    "fctcode": "2",
    "sky": "5",
    "wspd": {"english": "24", "metric": "39"},
    "wdir": {"dir": "W", "degrees": "263"},
    "wx": "Clear/Wind",
    "uvi": "0",
    "humidity": "32",
    "windchill": {"english": "-9999", "metric": "-9999"},
    "heatindex": {"english": "-9999", "metric": "-9999"},
    "feelslike": {"english": "49", "metric": "9"},
    "qpf": {"english": "0.0", "metric": "0"},
    "snow": {"english": "0.0", "metric": "0"},
    "pop": "0",
    "mslp": {"english": "30.02", "metric": "1017"}
    }

有了这些数据，我想从'hourly_forecast'列表中的第一个字典中获取'temp'值，其中'hour'为'22'。

我知道我可以使用下面的代码来获取第一个元素：

j_hour['hourly_forecast'][0]['temp']['english']

...但是这些数据总是根据我检索它的时间而变化，所以如果它是下午1点，它将首先"hour": "13"。

基本上我需要帮助，根据'小时'值来提取'temp'数据，并且列表总是在变化，所以我不能只根据元素序列来拉它。

总结一下，我从“我想要的'小时'开始打印”临时“键。

Answer 1

解决此问题的一个好方法是逐步缩小搜索范围，直到获得您正在寻找的信息为止。

首先，使用list comprehension获取所有英国温度，无论小时数：

>>> [d['temp']['english'] for d in j_hour['hourly_forecast']]
['50', '49', ...]

然后将其限制为小时为'22'的情况：

>>> [d['temp']['english'] for d in j_hour['hourly_forecast']
...                       if d['FCTTIME']['hour'] == '22']
['50']

现在你已经得到了你想要的温度，包裹在列表中。如果您使用括号[]替换括号()将列表推导转换为generator expression，则可以在其上调用next()以获取第一个（仅限于此案例）：

>>> next(d['temp']['english'] for d in j_hour['hourly_forecast']
...                           if d['FCTTIME']['hour'] == '22')
'50'

...etvoilà！

根据dict中的另一个值从dicts列表中检索一个值

1 个答案: