Boto3 - 如何使用 Python Boto3 从 scan() 输出中过滤出 attributeType？

Question

我正在使用 Boto3 检索并返回小型 dynamoDB 表中的所有数据。我的目标是从输出中删除 attributeTypes。

以下是我的输出：

    {"Items": [{"PresidentialCandidate_ID": {"S": "Trump"}, "Vote": {"N": "47"}}, {"PresidentialCandidate_ID": {"S": "Stein"}, "Vote": {"N": "16"}}, {"PresidentialCandidate_ID": {"S": "Dwayne"}, "Vote": {"N": "1"}}, {"PresidentialCandidate_ID": {"S": "none"}, "Vote": {"N": "11"}}, {"PresidentialCandidate_ID": {"S": "Johnson"}, "Vote": {"N": "13"}}, {"PresidentialCandidate_ID": {"S": "Clinton"}, "Vote": {"N": "22"}}], "Count": 6, "ScannedCount": 6}

我想要的输出：

    {"Items":[{"PresidentialCandidate_ID":"Trump","Vote":47},{"PresidentialCandidate_ID":"Stein","Vote":16},{"PresidentialCandidate_ID":"Dwayne","Vote":1},{"PresidentialCandidate_ID":"none","Vote":11},{"PresidentialCandidate_ID":"Johnson","Vote":13},{"PresidentialCandidate_ID":"Clinton","Vote":22}],"Count":6,"ScannedCount":6}

我尝试了以下方法：

    {"Items": [{"PresidentialCandidate_ID": {"S": "Trump"}, "Vote": {"N": "47"}}, {"PresidentialCandidate_ID": {"S": "Stein"}, "Vote": {"N": "16"}}, {"PresidentialCandidate_ID": {"S": "Dwayne"}, "Vote": {"N": "1"}}, {"PresidentialCandidate_ID": {"S": "none"}, "Vote": {"N": "11"}}, {"PresidentialCandidate_ID": {"S": "Johnson"}, "Vote": {"N": "13"}}, {"PresidentialCandidate_ID": {"S": "Clinton"}, "Vote": {"N": "22"}}], "Count": 6, "ScannedCount": 6}

关于如何过滤掉 attributeType 以获得我想要的输出有什么建议吗？

Answer 1

您可以尝试此代码，仅以您想要的方式返回数据。

import boto3
import json

dynamodb = boto3.client('dynamodb')


def lambda_handler(event, context):
    table = dynamodb.scan(TableName="PresidentialCandidate", ConsistentRead=True)
    items = table['Items']

    idx = 0
    for item in items:
        for key in item:
            value = list(item[key].values())[0]
            items[idx][key] = value
        idx += 1
    return items

您还可以将新的所需格式化对象一次性存储到表中。这样，attributeTypes 将不再反映，并且您可以在没有 attributeTypes 的情况下获得结果。您可以尝试下面的代码来做到这一点:)

import boto3
import json

dynamodb = boto3.client('dynamodb')


def lambda_handler(event, context):
    table = dynamodb.scan(TableName="PresidentialCandidate", ConsistentRead=True)
    items = table['Items']

    idx = 0
    for item in items:
        for key in item:
            value = list(item[key].values())[0]
            # added this line to write and replace the old format by the new formatted object
            dynamodb.put_item(TableName="PresidentialCandidate", Item=item)   
            items[idx][key] = value
        idx += 1
    return items