在 Python 中解析 JSON 结果时出现 KeyError

Posted 2023-03-16

【中文标题】在 Python 中解析 JSON 结果时出现 KeyError

【英文标题】：KeyError when parsing JSON results in Python

【发布时间】：2021-08-02 20:36:18

【问题描述】：

我在 Python 中解析 JSON 结果时遇到了 KeyError。我已经搜索了与 KeyError 相关的其他问题，但到目前为止没有一个答案有帮助。当我发出网络请求时

https://property.melissadata.net/v4/WEB/LookupProperty?id=MY_LICENSE_KEY&t=&cols=GrpPrimaryOwner&format=json&ff=5933 NE Garfield Avenue, Portland, OR, 97211

从浏览器返回结果

"Version":"5.0.1.1043","TransmissionResults":"","TotalRecords":1,"Records":["Results":"YS02,YS07,YC01","Parcel":"FIPSCode":"41051","UnformattedAPN":"R243379","FormattedAPN":"R243379","Legal":,"PropertyAddress":,"ParsedPropertyAddress":,"PrimaryOwner":"Name1Full":"PORTLAND PIEDMONT GUESTHOUSE L","Name1First":"","Name1Middle":"","Name1Last":"PORTLAND PIEDMONT GUESTHOUSE L"...

Python 代码的结果

import requests
import pprint
# api-endpoint
URL = “https://property.melissadata.net/v4/WEB/LookupProperty?id=MY_LICENSE_KEY&t=&cols=GrpPrimaryOwner&format=json”  
# location given here
location = "5933 NE Garfield Avenue, Portland, OR  97211"
# defining a params dict for the parameters to be sent to the API
PARAMS = 'address':location
# sending get request and saving the response as response object
r = requests.get(url = URL, params = PARAMS)
# extracting data in json format
data = r.json()
pprint.pprint(data)
name = data['Records'][0]['PrimaryOwner'][0]['Name1Full'][0]
print('name: ' + name)

是

'Records': ['Results': 'YE01'],
 'TotalRecords': 1,
 'TransmissionResults': '',
 'Version': '5.0.1.1043'
>>> name = data['Records'][0]['PrimaryOwner'][0]['Name1Full'][0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'PrimaryOwner'
>>> print('name: ' + name)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can only concatenate str (not "list") to str

我想从 JSON 结果中提取“PORTLAND PIEDMONT GUESTHOUSE L”的 Name1Full 值。感谢您提供的任何帮助。

解决方案： 当PARAMS = 'address':location 替换为PARAMS = 'ff':location 时，此方法有效

【参考方案1】：

鉴于您提供的json，我相信您应该尝试一下：

full_name = data['Records'][0]['PrimaryOwner']['Name1Full']

让我们看看它是如何工作的：

[Records][0] 访问：

"Results":"YS02,YS07,YC01","Parcel":"FIPSCode":"41051","UnformattedAPN":"R243379","FormattedAPN":"R243379","Legal":,"PropertyAddress":,"ParsedPropertyAddress":,"PrimaryOwner":"Name1Full":"PORTLAND PIEDMONT GUESTHOUSE L","Name1First":"","Name1Middle":"","Name1Last":"PORTLAND PIEDMONT GUESTHOUSE L"...

然后我们需要看到 Name1Full 是 PrimaryOwner 键的值，因此 [`Records'][0]['PrimaryOwner'] 访问：

"Name1Full":"PORTLAND PIEDMONT GUESTHOUSE L","Name1First":"","Name1Middle":"","Name1Last":"PORTLAND PIEDMONT GUESTHOUSE L"...

最后我们添加键 Name1Full 来访问具体值 [`Records'][0]['PrimaryOwner']['Name1First']：

返回：

"PORTLAND PIEDMONT GUESTHOUSE L"

【参考方案2】：

您在问题的第二部分中漂亮打印的 JSON 没有 'PrimaryOwner' 字段，这就是您收到关键错误的原因。

'Records': ['Results': 'YE01'],
 'TotalRecords': 1,
 'TransmissionResults': '',
 'Version': '5.0.1.1043'

我认为问题是：为什么您的程序获得的 JSON 数据与您的网络浏览器不同？我无法进一步帮助您，但也许其他人可以。

【讨论】：

感谢大家的帮助。这在 PARAMS = 'address':location 被替换为 PARAMS = 'ff':location 时有效

【参考方案3】：

我简化了问题。你没有得到你认为你得到的东西。下面这个sn-p重现了这个问题，我把多余的代码去掉了。

data = 'Records': ['Results': 'YE01'],
 'TotalRecords': 1,
 'TransmissionResults': '',
 'Version': '5.0.1.1043'
 
name = data['Records'][0]['PrimaryOwner'][0]['Name1Full'][0]
print('name: ' + name)

【参考方案4】：

当 PARAMS = 'address':location 替换为 PARAMS = 'ff':location