如果该值存在，则递增该值，否则在DynamoDB中添加一个新条目

import boto3
from botocore.exceptions import ClientError

# 初始化 DynamoDB 客户端
dynamodb = boto3.client('dynamodb')

table_name = 'YourTableName'
key = {'YourPartitionKey': 'your_partition_key_value'}
attribute_to_update = 'YourAttribute'
increment_by = 1

try:
    response = dynamodb.update_item(
        TableName=table_name,
        Key=key,
        UpdateExpression=f'set {attribute_to_update} = {attribute_to_update} + :val',
        ConditionExpression=f'attribute_exists({attribute_to_update})',
        ExpressionAttributeValues={':val': increment_by},
        ReturnValues='UPDATED_NEW'
    )
    print("Update successful:", response)
except ClientError as e:
    if e.response['Error']['Code'] == 'ConditionalCheckFailedException':
        # 如果条件检查失败，说明该值不存在，添加新条目
        response = dynamodb.put_item(
            TableName=table_name,
            Item={
                'YourPartitionKey': {'S': key['YourPartitionKey']},
                attribute_to_update: {'N': str(increment_by)}
            }
        )
        print("New item added:", response)
    else:
        print("Error:", e.response['Error']['Message'])