Python和DynamoDB十进制。不精确

Question

我正在尝试从我的dynamodb表中删除一个项目，但是却遇到此异常:

decimal.Inexact: [<class 'decimal.Inexact'>, <class 'decimal.Rounded'>]

我不知道如何解决它，有什么帮助吗？这是代码:

dynamodb = boto3.resource('dynamodb', region_name='***')

table = dynamodb.Table('***')

propid = 1234
column_set = Decimal(44.30912302164986)

print("Attempting a conditional delete...")

try:
    response = table.delete_item(
        Key={
            'hashkey': propid,
            'rangekey': column_set
        },
    )
except ClientError as e:
    if e.response['Error']['Code'] == "ConditionalCheckFailedException":
        print(e.response['Error']['Message'])
    else:
        raise
else:
    print("DeleteItem succeeded:")

以后编辑:

当我这样做时，它似乎无法正确存储:

year = decimal.Decimal(44.309123021649860)

它打印:

44.30912302164986016350667341612279415130615234375

Answer 1

我不知道为什么会这样，但是对于它的值(value)，您可以执行以下操作(基于boto3问题线程中的this comment):

with decimal.localcontext(boto3.dynamodb.types.DYNAMODB_CONTEXT) as ctx:
    ctx.traps[decimal.Inexact] = False
    ctx.traps[decimal.Rounded] = False
    column_set = ctx.create_decimal_from_float(v)

    response = table.delete_item(
        Key={
            'hashkey': propid,
            'rangekey': column_set
        },
    )