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python - 使用 xmltodict 在 Python 中访问标签内的一行

问题描述

我有一个看起来像这样的 xml 文件：

<!-- For the full list of available Crowd HTML Elements and their input/output documentation,
      please refer to https://docs.aws.amazon.com/sagemaker/latest/dg/sms-ui-template-reference.html -->

<!-- You must include crowd-form so that your task submits answers to MTurk -->
<crowd-form answer-format="flatten-objects">

    <!-- The crowd-classifier element will create a tool for the Worker to
 select the correct answer to your question.
          Your image file URLs will be substituted for the "image_url" variable below

          when you publish a batch with a CSV input file containing multiple image file URLs.

          To preview the element with an example image, try setting the src attribute to

          "https://s3.amazonaws.com/cv-demo-images/two-birds.jpg" -->
<crowd-image-classifier\n        
src= "https://someone@example.com/abcd.jpg"\n        
categories="[\'Yes\', \'No\']"\n        
header="abcd"\n        
name="image-contains">\n\n       
<!-- Use the short-instructions section for quick instructions that the Worker\n
will see while working on the task. Including some basic examples of\n              
good and bad answers here can help get good results. You can include\n              
any HTML here. -->\n        
<short-instructions>\n\n        
</crowd-image-classifier>
</crowd-form>
<!-- YOUR HTML ENDS -->

我想提取该行： 

src = https://someone@example.com/abcd.jpg

并将其分配给python中的变量。对 xml 解析有点新意：

我试过像：

hit_doc = xmltodict.parse(get_hit['HIT']['Question'])
image_url = hit_doc['HTMLQuestion']['HTMLContent']['crowd-form']['crowd-image-classifier']

错误：

    image_url = hit_doc['HTMLQuestion']['HTMLContent']['crowd-form']['crowd-image-classifier']
TypeError: string indices must be integers

如果我不访问代码中的['crowd-image-classifier']并将自己限制在

hit_doc = xmltodict.parse(get_hit['HIT']['Question'])
image_url = hit_doc['HTMLQuestion']['HTMLContent']

然后我得到完整的 xml 文件。

如何访问该 img src？

标签： pythonregexpython-3.xxmlxmltodict

解决方案

您可以使用 BeautifulSoup。请参阅下面的工作代码。

from bs4 import BeautifulSoup


html = '''<!-- For the full list of available Crowd HTML Elements and their input/output documentation,
      please refer to https://docs.aws.amazon.com/sagemaker/latest/dg/sms-ui-template-reference.html -->

<!-- You must include crowd-form so that your task submits answers to MTurk -->
<crowd-form answer-format="flatten-objects">

    <!-- The crowd-classifier element will create a tool for the Worker to
 select the correct answer to your question.
          Your image file URLs will be substituted for the "image_url" variable below

          when you publish a batch with a CSV input file containing multiple image file URLs.

          To preview the element with an example image, try setting the src attribute to

          "https://s3.amazonaws.com/cv-demo-images/two-birds.jpg" -->
<crowd-image-classifier\n        
src= "https://someone@example.com/abcd.jpg"\n        
categories="[\'Yes\', \'No\']"\n        
header="abcd"\n        
name="image-contains">\n\n       
<!-- Use the short-instructions section for quick instructions that the Worker\n
will see while working on the task. Including some basic examples of\n              
good and bad answers here can help get good results. You can include\n              
any HTML here. -->\n        
<short-instructions>\n\n        
</crowd-image-classifier>
</crowd-form>
<!-- YOUR HTML ENDS -->'''

soup = BeautifulSoup(html, 'html.parser')
element = soup.find('crowd-image-classifier')
print(element['src'])

输出

https://someone@example.com/abcd.jpg

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