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python - 在python中对日期对象进行排序列出了不正确的顺序

问题描述

所以我有我的 python 脚本，它列出了关于每个 ec2 实例的报告。我有一个函数可以对实例的 networkattatchtime 进行排序，但是每次我使用 stftime 来格式化日期的输出时，它似乎会弄乱排序并以随机顺序列出实例，而不是按最旧的 CreationDateTime。我得到的输出如下：

i-09dc54328002240ff,Aug 05 2021,asg-workxxx
i-048e92c5a4741d2b1,Mar 09 2017,False
i-0d649cebdf54bd2f4,Mar 12 2020,asg-dyyyyy
i-0ff596f1dc01b61d8,Mar 17 2021,asg-base-test
i-06db4eb158ad0b071,May 12 2021,False
i-0f285277529543462,May 18 2018,False
i-0f67cf99fb9f96c3f,Oct 14 2020,asg-elk-test
i-01734dfef0159c5c8,Oct 20 2020,asg-lb-test
i-0539c8dfc839cbfda,Oct 26 2020,asg-stand-base-test

您可以看到 CreationDateTime 未按排序顺序。

我的代码如下：

       response = ec2_client.describe_instances(
       
        MaxResults=10
    )
    
    # return json data from describe instances and filter what is needed
    instances = (len(response['Reservations']))
    header_row = 'InstanceID, CreationDateTime, AutoScalingGroupName' + '\n'
  

    for x in range(instances):

        # Get InstanceId
        instance_id = (response['Reservations'][x]
                       ['Instances'][0]['InstanceId'])
        # Get NetworkInterfacws AttatchTime
        network_interface_id = (
            response['Reservations'][x]['Instances'][0]['NetworkInterfaces'][0]['NetworkInterfaceId'])
        
        network_interface_details = ec2_client.describe_network_interfaces(
            NetworkInterfaceIds=[network_interface_id])
        networkinterface_id_attachedtime = network_interface_details[
            'NetworkInterfaces'][0]['Attachment']['AttachTime']
    
        time_between_insertion = datetime.now(
            timezone.utc) - networkinterface_id_attachedtime

        # Get Autoscaling GroupName
        tags = (response['Reservations'][x]['Instances'][0]['Tags'])
        autoscaling_group_name = get_tag(tags, 'aws:autoscaling:groupName')

        # print results
        if time_between_insertion.days > max_age:
            line = '{},{},{}'.format(
                instance_id, formatted_date_networkinterface_id, autoscaling_group_name)
            instances_list.append(line)

    sorted_list= sorted(instances_list, key=lambda v: v.split(',')[1])

    for instance in sorted_list:
        print(instance) ```

标签： pythonpython-3.xsortingdatedatetime

解决方案

要解析日期，您可以使用datetime.datetime.strptime：

import datetime  # strptime
import operator  # itemgetter

data_unparsed = ['i-09dc54328002240ff,Aug 05 2021,asg-workxxx',
'i-048e92c5a4741d2b1,Mar 09 2017,False',
'i-0d649cebdf54bd2f4,Mar 12 2020,asg-dyyyyy',
'i-0ff596f1dc01b61d8,Mar 17 2021,asg-base-test',
'i-06db4eb158ad0b071,May 12 2021,False',
'i-0f285277529543462,May 18 2018,False',
'i-0f67cf99fb9f96c3f,Oct 14 2020,asg-elk-test',
'i-01734dfef0159c5c8,Oct 20 2020,asg-lb-test',
'i-0539c8dfc839cbfda,Oct 26 2020,asg-stand-base-test']

data = [((row := s.split(','))[0], datetime.datetime.strptime(row[1], '%b %d %Y'), row[2]) for s in data_unparsed]

data_sorted = sorted(data, key=operator.itemgetter(1))
print(data_sorted)
# [('i-048e92c5a4741d2b1', datetime.datetime(2017, 3, 9, 0, 0), 'False'),
#  ('i-0f285277529543462', datetime.datetime(2018, 5, 18, 0, 0), 'False'),
#  ('i-0d649cebdf54bd2f4', datetime.datetime(2020, 3, 12, 0, 0), 'asg-dyyyyy'),
#  ('i-0f67cf99fb9f96c3f', datetime.datetime(2020, 10, 14, 0, 0), 'asg-elk-test'),
#  ('i-01734dfef0159c5c8', datetime.datetime(2020, 10, 20, 0, 0), 'asg-lb-test'),
#  ('i-0539c8dfc839cbfda', datetime.datetime(2020, 10, 26, 0, 0), 'asg-stand-base-test'),
#  ('i-0ff596f1dc01b61d8', datetime.datetime(2021, 3, 17, 0, 0), 'asg-base-test'),
#  ('i-06db4eb158ad0b071', datetime.datetime(2021, 5, 12, 0, 0), 'False'),
#  ('i-09dc54328002240ff', datetime.datetime(2021, 8, 5, 0, 0), 'asg-workxxx')]

或者，作为单线：

data_sorted = sorted(data_unparsed, key=lambda s: datetime.datetime.strptime(s.split(',')[1], '%b %d %Y'))

print(data_sorted)
# ['i-048e92c5a4741d2b1,Mar 09 2017,False',
#  'i-0f285277529543462,May 18 2018,False',
#  'i-0d649cebdf54bd2f4,Mar 12 2020,asg-dyyyyy',
#  'i-0f67cf99fb9f96c3f,Oct 14 2020,asg-elk-test',
#  'i-01734dfef0159c5c8,Oct 20 2020,asg-lb-test',
#  'i-0539c8dfc839cbfda,Oct 26 2020,asg-stand-base-test',
#  'i-0ff596f1dc01b61d8,Mar 17 2021,asg-base-test',
#  'i-06db4eb158ad0b071,May 12 2021,False',
#  'i-09dc54328002240ff,Aug 05 2021,asg-workxxx']

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