如何在更新的 json 文件中获取最后日期？答案

【问题标题】：How to get last date in updated json file?如何在更新的 json 文件中获取最后日期？
【发布时间】：2021-07-27 03:01:52
【问题描述】：

我正在从 json 文件中获取我的数据，并且数据每天都会更新。 我怎样才能只获得该 json 文件中的最新日期？每个国家/地区的核心

这是我获取 json 数据的代码：

# Print Daily Updated Report from JSON file from this (URL)

import json
import urllib.request, json 

url = "https://opendata.ecdc.europa.eu/covid19/nationalcasedeath_eueea_daily_ei/json/"
data = urllib.request.urlopen(url).read().decode()

obj = json.loads(data)
for p in obj['records']:
        a= ('Country: ' + p['countriesAndTerritories'])
        b= ('Date: ' + p['dateRep'])
        c=('Cases: ' + str(p['cases']))
        d=('Deaths: ' + str(p['deaths']))
        AllData = (a,b,c,d)
        print(AllData)

【问题讨论】：

标签： python json web-scraping urllib

【解决方案1】：

您只需要一个latest_day变量库

完整代码为：

import json
import urllib.request, json 

url = "https://opendata.ecdc.europa.eu/covid19/nationalcasedeath_eueea_daily_ei/json/"
data = urllib.request.urlopen(url).read().decode()

obj = json.loads(data)
latest_day = obj['records'][0]['dateRep']

for p in obj['records']:
    if p['dateRep'] == latest_day:
        a= ('Country: ' + p['countriesAndTerritories'])
        b= ('Date: ' + p['dateRep'])
        c=('Cases: ' + str(p['cases']))
        d=('Deaths: ' + str(p['deaths']))
        AllData = (a,b,c,d)
        print(AllData)

【讨论】：

【解决方案2】：

您可以使用itertools.groupby 对元素进行分组，然后使用max() 和自定义key= 在组内搜索最新日期。例如：

import json
import urllib.request, json
from itertools import groupby
from datetime import datetime

url = "https://opendata.ecdc.europa.eu/covid19/nationalcasedeath_eueea_daily_ei/json/"
data = urllib.request.urlopen(url).read().decode()

obj = json.loads(data)

for country, group in groupby(
    sorted(obj["records"], key=lambda k: k["countriesAndTerritories"]),
    lambda k: k["countriesAndTerritories"],
):
    mx = max(group, key=lambda k: datetime.strptime(k["dateRep"], "%d/%m/%Y"))
    print(country)
    print(json.dumps(mx, indent=4))
    print("-" * 80)

打印：

Austria
{
    "dateRep": "04/05/2021",
    "day": "04",
    "month": "05",
    "year": "2021",
    "cases": 888,
    "deaths": 25,
    "countriesAndTerritories": "Austria",
    "geoId": "AT",
    "countryterritoryCode": "AUT",
    "popData2020": "8901064",
    "continentExp": "Europe"
}
--------------------------------------------------------------------------------
Belgium
{
    "dateRep": "04/05/2021",
    "day": "04",
    "month": "05",
    "year": "2021",
    "cases": 0,
    "deaths": 0,
    "countriesAndTerritories": "Belgium",
    "geoId": "BE",
    "countryterritoryCode": "BEL",
    "popData2020": "11522440",
    "continentExp": "Europe"
}
--------------------------------------------------------------------------------
Bulgaria
{
    "dateRep": "04/05/2021",
    "day": "04",
    "month": "05",
    "year": "2021",
    "cases": 631,
    "deaths": 56,
    "countriesAndTerritories": "Bulgaria",
    "geoId": "BG",
    "countryterritoryCode": "BGR",
    "popData2020": "6951482",
    "continentExp": "Europe"
}
--------------------------------------------------------------------------------

...

【讨论】：