根据 region 和 eventTypeCode 获取最近的事件

Question

我有以下 json 数据，如何通过在 python 中对startTime进行排序来获取基于region和eventTypeCode以及最新事件的最新记录？需要忽略eventTypeCode的重复项。有什么办法可以在 python 中比较这个startTime，找出最近的记录并只返回那个记录？样本数据：   "ResponseMetadata": {      "HTTPHeaders": {         "content-length": "1478",         "content-type": "application/x-amz-json-1.1",         "date": "Mon, 27 Jan 2020 21:24:47 GMT",         "x-amzn-requestid": "a84471fc-8bde-4404-854e-c1656884cac5"      },      "HTTPStatusCode": 200,      "RequestId": "a84471fc-8bde-4404-854e-c1656884cac5",      "RetryAttempts": 0   },   "events": [      {         "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",         "startTime": "2020-01-15 11:50:00-06:00",         "region": "us-east-1"      },      {         "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",         "startTime": "2019-11-26 02:59:00-06:00",         "region": "us-east-1"      },      {         "eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",         "startTime": "2020-01-27 12:36:00-06:00",         "region": "us-east-1"      },      {         "eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",         "startTime": "2019-11-18 16:04:00-06:00",         "region": "us-east-1"      },      {         "eventTypeCode": "AWS_MARKETPLACE_OPERATIONAL_NOTIFICATION",         "startTime": "2019-11-11 11:30:00-06:00",         "region": "us-east-1"      },      {         "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",         "startTime": "2020-01-10 11:55:00-06:00",         "region": "us-west-1"      },      {         "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",         "startTime": "2019-11-13 02:15:00-06:00",         "region": "us-west-1"      },   ]}预期输出：   "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",   "startTime": "2020-01-15 11:50:00-06:00",   "region": "us-east-1"},{   "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",   "startTime": "2020-01-10 11:55:00-06:00",   "region": "us-west-1"}

Answer 1

import datetime as dt

from dateutil.parser import parse

import json

def events_equal(event1, event2):

    return event1["eventTypeCode"] == event2["eventTypeCode"] and event1["region"] == event2["region"]

json_data = ### Insert your json data string here ###

parsed_json_data = json.loads(json_data)

filtered_events = []

for parsed_event in parsed_json_data["events"]:

    already_present = False

    ## for every event, check if we've already added it to the filtered list

    for filtered_event_index in range(len(filtered_events)):

        if events_equal(parsed_event, filtered_events[filtered_event_index]):

            already_present = True

            ## Convert startTime strings to datetime object for comparison

            parsed_event_date = parse(parsed_event["startTime"])

            filtered_event_date = parse(filtered_events[filtered_event_index]["startTime"])

            ## Use parse if on an older version of python, otherwise

            ## strptime can handle the conversion

            ## parsed_event_date = dt.datetime.strptime(parsed_event["startTime"], '%Y-%m-%d %H:%M:%S%z')

            ## filtered_event_date = dt.datetime.strptime(filtered_events[filtered_event_index]["startTime"], '%Y-%m-%d %H:%M:%S%z')

            if parsed_event_date > filtered_event_date:

                ## if parsed event date is newer, replace the one already present

                filtered_events[filtered_event_index] = parsed_event

    if not already_present:

        filtered_events.append(parsed_event)

## build the new json object

filtered_events = {"events": filtered_events}

print(json.dumps(filtered_events, indent=4))

输出：

{

    "events": [

        {

            "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",

            "startTime": "2020-01-15 11:50:00-06:00",

            "region": "us-east-1"

        },

        {

            "eventTypeCode": "AWS_TRUSTEDADVISOR_OPERATIONAL_NOTIFICATION",

            "startTime": "2020-01-27 12:36:00-06:00",

            "region": "us-east-1"

        },

        {

            "eventTypeCode": "AWS_MARKETPLACE_OPERATIONAL_NOTIFICATION",

            "startTime": "2019-11-11 11:30:00-06:00",

            "region": "us-east-1"

        },

        {

            "eventTypeCode": "AWS_RDS_SECURITY_NOTIFICATION",

            "startTime": "2020-01-10 11:55:00-06:00",

            "region": "us-west-1"

        }

    ]

}

这仅适用于从 python 3.7 开始，早期版本的 strptime 将仅以-0600and not的形式解析 UTC 偏移量-06:00。

编辑：我用 dateutil 解析器替换了 strptime 调用，它将与早期版本的 python 一起使用。