下面的代码片段获取特定文件夹下的所有对象，并检查上次修改的文件是否是在您指定的时间之后创建的：
将YEAR,MONTH, DAY替换为您的值。

import boto3
import datetime
#bucket Name
bucket_name = 'BUCKET NAME'
#folder Name
folder_name = 'FOLDER NAME'
#bucket Resource
s3 = boto3.resource('s3')
bucket = s3.Bucket(bucket_name)    
def lambda_handler(event, context):
     for file in bucket.objects.filter(Prefix= folder_name):
         #compare dates 
         if file.last_modified.replace(tzinfo = None) > datetime.datetime(YEAR,MONTH, DAY,tzinfo = None):
             #print results
             print('File Name: %s ---- Date: %s' % (file.key,file.last_modified))

下面的代码片段将使用s3 Object类get（）操作仅返回满足IfModifiedSince日期时间参数的文件。脚本将打印文件，这是原始问题，但也将文件保存在本地。

import boto3
import io
from datetime import date, datetime, timedelta

# Defining AWS S3 resources
s3 = boto3.resource('s3')
bucket = s3.Bucket('<bucket_name>')
prefix = '<object_key_prefix, if any>'

# note this based on UTC time
yesterday = datetime.fromisoformat(str(date.today() - timedelta(days=1)))

# function to retrieve Streaming Body from S3 with timedelta argument
def get_object(file_name):
    try:
        obj = file_name.get(IfModifiedSince=yesterday)
        return obj['Body']
    except:
        False

# obtain a list of s3 Objects with prefix filter
files = list(bucket.objects.filter(Prefix=prefix))

# Iterating through the list of files
# Loading streaming body into a file with the same name
# Printing file name and saving file
# Note skipping first file since it's only the directory

for file in files[1:]:
    file_name = file.key.split(prefix)[1] # getting the file name of the S3 object
    s3_file = get_object(file) # streaming body needing to iterate through
    if s3_file: # meets the modified by date
        print(file_name) # prints files not modified since timedelta
        try:
            with io.FileIO(file_name, 'w') as f:
                for i in s3_file: # iterating though streaming body
                    f.write(i)
        except TypeError as e:
            print(e, file)

这里是一个更优化的解决方案，可以通过LastModified字段过滤对象键。

s3 = boto3.client("s3")
s3_paginator = s3.get_paginator('list_objects_v2')
s3_iterator = s3_paginator.paginate(Bucket="SampleBucket")
filtered_iterator = s3_iterator.search(
    "Contents[?to_string(LastModified)>='\"2023-03-01 00:00:00+00:00\"'].Key"
)

for key_data in filtered_iterator:
    print(key_data)

您可以修改迭代器搜索字符串以获取必要的字段。