Question

我有这段代码从字典对象中提取值

extracted_value = response_content["retrievePolicyBillingSummariesResponse"]["billingSummaries"]["policyBillingSummary"][0]["billingSummary"]["lastPayment"]["status"]
extracted_value = response_content["retrievePolicyBillingSummariesResponse"]["billingSummaries"]["policyBillingSummary"][0]["billingSummary"]["bill"]["dueDate"]

这些只是两个样本，但我有十几个具有不同的键/路径组合。我怎样才能使用模块调用它们并执行类似的操作

def get_value_from_content (response_content, my_path):
    # how can I use the value in my_path as the key instead of this hard coded path ?
    extracted_value =  response_content["retrievePolicyBillingSummariesResponse"]["billingSummaries"]["policyBillingSummary"][0]["billingSummary"]["lastPayment"]["status"]
    #extracted_value = response_content using my_path is what I would like to do
    return extracted_value

#I get this from a REST API call but skipping the code here and just hard coding to ask the question here
response_content = {u'retrievePolicyBillingSummariesResponse': {u'billingSummaries': {u'policyBillingSummary': [{u'policy': {u'status': u'A', u'policyNumber': u'xyz123', u'writingCompany': u'FBI', u'renewalFlag': u'false', u'convertedRenewalOffer': u'false', u'termExpirationDate': u'2017-06-26', u'lineOfBusiness': u'PC', u'termEffectiveDate': u'2016-06-26', u'riskState': u'CA', u'insureds': {u'namedInsuredSummary': [{u'preferredPostalAddress': {u'streetAddressLine': u'1 disney', u'cityName': u'palo alto', u'zipCode': u'94100', u'isoRegionCode': u'CA'}, u'name': {u'lastName': u'DOE', u'fullName': u'john doe', u'firstName': u'john'}}]}, u'additionalInterests': {u'additionalInterest': [{u'billTo': u'N', u'name': {u'partyType': u'Organization'}}]}, u'type': u'PA', u'statusDescription': u'Active', u'dataSource': u'from_heaven'}, u'billingSummary': {u'paymentRestriction': u'false', u'nextInstallmentAmount': u'0.00', u'bill': {u'installmentNumber': u'1', u'statementDate': u'2016-06-26', u'paymentPlan': u'Direct', u'installmentAmount': u'12.00', u'totalBillAmountDue': u'1.76', u'previousBalance': u'0.00', u'dueDate': u'2016-06-26', u'billingPlan': u'ANN'}, u'lastPayment': {u'status': u'A'}, u'currentBalance': u'16.66', u'payOffAmount': u'15.66', u'isRestrictedToPay': u'false'}}]}}}

my_path = '["retrievePolicyBillingSummariesResponse"]["billingSummaries"]["policyBillingSummary"][0]["billingSummary"]["lastPayment"]["status"]'
get_extracted_item = get_value_from_content(response_content,my_path)

my_path = '["retrievePolicyBillingSummariesResponse"]["billingSummaries"]["policyBillingSummary"][0]["billingSummary"]["bill"]["dueDate"]'
get_extracted_item = get_value_from_content(response_content,my_path)

Answer 1

首先，编写像

这样的小实用功能会更容易

def extract_from_dictionary(dictionary, *keys_or_indexes):
    value = dictionary
    for key_or_index in keys_or_indexes:
        value = value[key_or_index]
    return value

我们可以从您的示例中看到，有一个名为billingSummary的对象出现在必需的路径中，因此我们可以避免使用

的样板

def get_billing_summary(response_content):
    return extract_from_dictionary(
        response_content,
        "retrievePolicyBillingSummariesResponse",
        "billingSummaries",
        "policyBillingSummary",
        0,
        "billingSummary")

然后我们可以简单地写

def get_value_from_content(response_content, *keys):
    billing_summary = get_billing_summary(response_content)
    extracted_value = extract_from_dictionary(billing_summary,
                                              *keys)
    return extracted_value

获取所需的对象，如

last_payment_status = get_value_from_content(response_content,
                                             "lastPayment",
                                             "status")
bill_due_date = get_value_from_content(response_content,
                                       "bill",
                                       "dueDate")
print("last_payment_status:", last_payment_status)
print("bill_due_date:", bill_due_date)

给我们

last_payment_status: A
bill_due_date: 2016-06-26

Answer 2

如何使用迭代解决方案，如下所示：

response_content = {u'retrievePolicyBillingSummariesResponse': {u'billingSummaries': {u'policyBillingSummary': [{u'policy': {u'status': u'A', u'policyNumber': u'xyz123', u'writingCompany': u'FBI', u'renewalFlag': u'false', u'convertedRenewalOffer': u'false', u'termExpirationDate': u'2017-06-26', u'lineOfBusiness': u'PC', u'termEffectiveDate': u'2016-06-26', u'riskState': u'CA', u'insureds': {u'namedInsuredSummary': [{u'preferredPostalAddress': {u'streetAddressLine': u'1 disney', u'cityName': u'palo alto', u'zipCode': u'94100', u'isoRegionCode': u'CA'}, u'name': {u'lastName': u'DOE', u'fullName': u'john doe', u'firstName': u'john'}}]}, u'additionalInterests': {u'additionalInterest': [{u'billTo': u'N', u'name': {u'partyType': u'Organization'}}]}, u'type': u'PA', u'statusDescription': u'Active', u'dataSource': u'from_heaven'}, u'billingSummary': {u'paymentRestriction': u'false', u'nextInstallmentAmount': u'0.00', u'bill': {u'installmentNumber': u'1', u'statementDate': u'2016-06-26', u'paymentPlan': u'Direct', u'installmentAmount': u'12.00', u'totalBillAmountDue': u'1.76', u'previousBalance': u'0.00', u'dueDate': u'2016-06-26', u'billingPlan': u'ANN'}, u'lastPayment': {u'status': u'A'}, u'currentBalance': u'16.66', u'payOffAmount': u'15.66', u'isRestrictedToPay': u'false'}}]}}}

my_path = [
    "retrievePolicyBillingSummariesResponse",
    "billingSummaries",
    "policyBillingSummary",
    0,
    "billingSummary",
    "lastPayment",
    "status"
]

def get_value_from_content(extraction, my_path):
    for el in my_path:
        if isinstance(extraction, dict):
            extraction = extraction.get(el, extraction)
        else:
            extraction = extraction[el]
    return extraction

extraction = get_value_from_content(response_content, my_path)
print(extraction)

函数get_value_from_content甚至可以比之前更短，即

def get_value_from_content(extraction, my_path):
    for el in my_path:
        extraction = extraction[el]
    return extraction

get_value_from_content的最后一个版本更容易抛出例外情况，例如：误读了路径组件的链接。因此，仍然需要确定字符串对象my_path是人为还是机器制造的。

在这两种情况下，返回"A"。 Python 2和3中的 经过测试 。另请注意，自the former is usually faster than the latter以来，我赞成对递归的迭代解决方案。在20% and 40% faster in the present case之间。

话虽如此，这并未解决问题，因为my_path最初不是列表对象，而是字符串对象。 要解决问题，首先要将此字符串转换为键/索引列表，然后按上述方法处理它。或者，正如@Minji所做的那样，人们可能想要使用python内置函数eval。即使使用此函数被称为a bad practice，我也想知道在这种情况下，eval的使用在多大程度上无法描述为最佳方式。

Answer 3

递归函数怎么样？

def get_value(response, index):
    if len(index) > 1:
        return get_value(response[index[0]], index[1:])
    else:
        return response[index[0]]

index = ["retrievePolicyBillingSummariesResponse", "billingSummaries", "policyBillingSummary", 0, "billingSummary", "lastPayment", "status"]

get_value(response_content, index)

Answer 4

eval()将字符串解释为代码

def get_value_from_content (response_content, my_path):
    # string is arguments name
    item = "response_content" + my_path
    return eval(item)

使用python

4 个答案: