我正在尝试扫描列名为 S3KeyID 的值,并且正在寻找值"newkey"。
当我在测试中运行它时,它会扫描 dynamoDB 表中的所有 3 个项目,并找到 3 个结果并且没有匹配项。
import boto3
import json
import decimal
import calendar
import datetime
from boto3.dynamodb.conditions import Key, Attr
def lambda_handler(event, context):
StartDateTime = datetime.datetime.now() - datetime.timedelta(minutes=10000)
EndDateTime = datetime.datetime.now()
# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
def default(self, o):
if isinstance(o, decimal.Decimal):
return str(o)
return super(DecimalEncoder, self).default(o)
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('Overwatch')
print("Overwatch old messages")
response = table.scan(
#ExpressionAttributeNames = {'ST' : 'S3KeyID'},
FilterExpression = "S3KeyID = :key",
ExpressionAttributeValues =
{ #":dateStart": {"S": StartDateTime},
#":dateEnd": {"S": EndDateTime},
":key" : {"S" : "newkey"}
# ":S3KeyID : 1222433"
}
#ProjectionExpression="S3KeyID"
)
for i in response[u'Items']:
print(json.dumps(i, cls=DecimalEncoder))
return response
查看结果:
Items": [],
"Count": 0,
"ScannedCount": 3,
我想效果更好:
response = table.scan(
FilterExpression = Attr('S3KeyID').eq('newkey')
)
阅读文档以获取更多示例。这是我的灵感:
同样,您可以根据项目的属性扫描表。例如,这将扫描年龄小于 27 岁的所有用户:
response = table.scan(
FilterExpression=Attr('age').lt(27)
)
items = response['Items']
print(items)