从 Clinicaltrials.gov 解析 XML

Question

我正在尝试解析来自临床试验网站的主要终点。我对阅读 XML 文件有点陌生，我确定我搞砸了。

import requests
import xml.etree.ElementTree as etree

r = requests.get('https://clinicaltrials.gov/api/query/full_studies?expr=heart+attack')
root = etree.fromstring(r.content)

for child in root.iter('Field'):
    print(child.tag, child.attrib)

我明白了：

Field {'Name': 'StartDate'}
Field {'Name': 'StartDateType'}
Field {'Name': 'PrimaryCompletionDate'}
Field {'Name': 'PrimaryCompletionDateType'}
Field {'Name': 'PrimaryOutcomeMeasure'}
Field {'Name': 'PrimaryOutcomeDescription'}
Field {'Name': 'PrimaryOutcomeTimeFrame'}
Field {'Name': 'CompletionDate'}...

所以当我回去尝试时：

for child in root.iter('Field'):
    print(child.tag['Name'], child.attrib['PrimaryOutcomeMeasure'])

我收到以下错误：

---

KeyError                                  Traceback (most recent call last)
<ipython-input-62-f201e3c2a2b1> in <module>
      9 
     10 for child in root.iter('Field'):
---> 11     print(child.attrib['PrimaryOutcomeMeasure'])

KeyError: 'PrimaryOutcomeMeasure'

发生了什么事？

Answer 1

我建议你使用其他库编写代码，简单易读。

from simplified_scrapy import SimplifiedDoc, utils, req
xml = req.get(
    'https://clinicaltrials.gov/api/query/full_studies?expr=heart+attack'
)
doc = SimplifiedDoc(xml)
PrimaryOutcomeMeasure = doc.select('Field@Name="PrimaryOutcomeMeasure"')
print (PrimaryOutcomeMeasure.text)
# Or
PrimaryOutcome = doc.select('Struct@Name="PrimaryOutcome"')
print (PrimaryOutcome.select('Field@Name="PrimaryOutcomeMeasure"').text)

结果：

In-hospital mortality of the patients with acute myocardial infarction in different-level hospitals across China
In-hospital mortality of the patients with acute myocardial infarction in different-level hospitals across China

这里有更多示例：https://github.com/yiyedata/simplified-scrapy-demo/tree/master/doc_examples