我對python很陌生。除了我的以下代碼之外，是否還有檢查python中存在的特定JSON對象？承認我下面的代碼不是很好的做法所以需要知道哪種方法更好檢查和易于維護？這是 JSON 響應：[ { "MessageId": "250e37a8-d779-48a1-9941-84219a82513e", "ReceiptHandle": "AQEBjualXe2ywqTgIVmCNI5sKj7r48werf84HHA2BWZimwiEXLFxA/MiPBclK048NZBtOnM3dSDfoiwwqoNTPxTRz+IChd8McziweCxHX6texjAOi/MyAQjCWP+2hJPoxzQgXx9kjnKbepKlcgxhpOiQZe6WiSIq0dXwHHXSA7SP0g9NIR/dU38b+wmo0m2q7MNVfSct967EKF49wow9RHyFMO8iD8fH93PYT9om5NdUha3dvkWnisKcfuO5pZY3LLXPAnuZT/VfqxJjmPqb98iepBfqFb6SpM/02IVSql81XKJEbMBc4zPHp/Uace6e4UDGsn/hPCVsqQsTzrbKCR+ovpkhXipWwTYSlgsLe/o43k0UxhCN8eKhg835KuUkskA3T8C5Q6v6xgznlR7JJuhZpg==", "MD5OfBody": "bbdc5fdb8be7251f5c910905db994bab", "Body": "Information about current NY Times fiction bestseller for week of 12/11/2016.", "Attributes": { "SentTimestamp": "1553851566164" }, "MD5OfMessageAttributes": "d25a6aea97eb8f585bfa92d314504a92", "MessageAttributes": { "Author": { "StringValue": "John Grisham", "DataType": "String" }, "Title": { "StringValue": "The Whistler", "DataType": "String" }, "WeeksOn": { "StringValue": "6", "DataType": "Number" } } }]這是我要檢查的python代碼：if 'Messages' in response: message = response['Messages'][0] receipt_handle = message['ReceiptHandle'] sqs.delete_message( QueueUrl=queue_url, ReceiptHandle=receipt_handle ) print('Received and deleted message: %s' % message)else: print('Message not received yet')請讓我知道上面的代碼是否是好的做法。
3 回答
大話西游666
TA貢獻1817條經驗 獲得超14個贊
您可以結帳的另一個選項是我在使用 JSON 數據時實際上更喜歡的選項，是從 JSON 數據中創建一個對象并使用該hasattr方法。這將防止您開始過度使用 try-except 塊，還可以使您的代碼更易于理解。使用您的數據的示例如下：
data= '''
{
"MessageId": "250e37a8-d779-48a1-9941-84219a82513e",
"ReceiptHandle": "AQEBjualXe2ywqTgIVmCNI5sKj7r48werf84HHA2BWZimwiEXLFxA/MiPBclK048NZBtOnM3dSDfoiwwqoNTPxTRz+IChd8McziweCxHX6texjAOi/MyAQjCWP+2hJPoxzQgXx9kjnKbepKlcgxhpOiQZe6WiSIq0dXwHHXSA7SP0g9NIR/dU38b+wmo0m2q7MNVfSct967EKF49wow9RHyFMO8iD8fH93PYT9om5NdUha3dvkWnisKcfuO5pZY3LLXPAnuZT/VfqxJjmPqb98iepBfqFb6SpM/02IVSql81XKJEbMBc4zPHp/Uace6e4UDGsn/hPCVsqQsTzrbKCR+ovpkhXipWwTYSlgsLe/o43k0UxhCN8eKhg835KuUkskA3T8C5Q6v6xgznlR7JJuhZpg==",
"MD5OfBody": "bbdc5fdb8be7251f5c910905db994bab",
"Body": "Information about current NY Times fiction bestseller for week of 12/11/2016.",
"Attributes": {"SentTimestamp": "1553851566164"},
"MD5OfMessageAttributes": "d25a6aea97eb8f585bfa92d314504a92",
"MessageAttributes": {"Author": {"StringValue": "John Grisham","DataType": "String"},"Title": {"StringValue": "The Whistler","DataType": "String"},"WeeksOn": {"StringValue": "6","DataType": "Number"}}
} '''
import json
class Response:
def __init__(self, data):
self.__dict__ = json.loads(data)
response = Response(data)
if hasattr(response , 'MessageId'):
receipt_handle = response.ReceiptHandle
print("Received and deleted message: %s" % response.MessageId)
else:
print('Message not received yet')
輸出：
Received and deleted message: 250e37a8-d779-48a1-9941-84219a82513e
瀟瀟雨雨
TA貢獻1833條經驗 獲得超4個贊
由于響應是listdict 的：
j_data = [{'MessageId': '250e37a8-d779-48a1-9941-84219a82513e',
'ReceiptHandle': 'AQEBjualXJJuhZpg==', 'MD5OfBody': 'bbdc5f905db994bab',
'Body': 'Information about current NY Times fiction bestseller for week of 12/11/2016.',
'Attributes': {'SentTimestamp': '1553851566164'},
'MD5OfMessageAttributes': 'd25a6aea97eb8f585bfa92d314504a92',
'MessageAttributes': {'Author': {'StringValue': 'John Grisham', 'DataType': 'String'},
'Title': {'StringValue': 'The Whistler', 'DataType': 'String'},
'WeeksOn': {'StringValue': '6', 'DataType': 'Number'}}}
]
for data in j_data:
try:
if 'MessageId' in data:
message = data['MessageId']
receipt_handle = data['ReceiptHandle']
sentTimeStamp = data['Attributes']['SentTimestamp']
print(message)
print(receipt_handle)
print(sentTimeStamp)
except KeyError:
print("Some custom message here")
輸出：
250e37a8-d779-48a1-9941-84219a82513e
AQEBjualXJJuhZpg==
1553851566164
編輯：
另一種方法是在訪問之前檢查每個鍵，即（ReceiptHandle從響應中刪除elem）：
j_data = [{'MessageId': '250e37a8-d779-48a1-9941-84219a82513e',
'MD5OfBody': 'bbdc5f905db994bab',
'Body': 'Information about current NY Times fiction bestseller for week of 12/11/2016.',
'Attributes': {'SentTimestamp': '1553851566164'},
'MD5OfMessageAttributes': 'd25a6aea97eb8f585bfa92d314504a92',
'MessageAttributes': {'Author': {'StringValue': 'John Grisham', 'DataType': 'String'},
'Title': {'StringValue': 'The Whistler', 'DataType': 'String'},
'WeeksOn': {'StringValue': '6', 'DataType': 'Number'}}}
]
for data in j_data:
try:
if 'MessageId' in data:
message = data['MessageId']
print(message)
if 'ReceiptHandle' in data:
receipt_handle = data['ReceiptHandle']
print(receipt_handle)
if 'Attributes' in data:
sentTimeStamp = data['Attributes']['SentTimestamp']
print(sentTimeStamp)
except KeyError:
print("Some custom message here")
輸出：
250e37a8-d779-48a1-9941-84219a82513e
1553851566164
慕后森
TA貢獻1802條經驗 獲得超5個贊
首先，正如已經提到的，示例 json 不包含 key Messages。我認為你的代碼看起來不錯。但是，如果您有一個沒有密鑰的 json 的情況Messages非常罕見，我會嘗試除了塊。
try:
message = response['Messages'][0]
receipt_handle = message['ReceiptHandle']
sqs.delete_message(
QueueUrl=queue_url,
ReceiptHandle=receipt_handle
)
print('Received and deleted message: %s' % message)
except KeyError:
print('Message not received yet')
每次獲得“正確”的 json 時，這都會快得多。但是當你得到一個缺少密鑰的 json 時會變慢。因此，也許您需要了解是否經常出現缺少密鑰的天氣。
但這取決于用例。而我的回答只是我個人在類似用例中的看法和經驗
添加回答
舉報
0/150
提交
取消