使用 ElementTree 从 xml 标记中获取所有子项答案

【问题标题】：Get all the children from xml tag using ElementTree使用 ElementTree 从 xml 标记中获取所有子项
【发布时间】：2018-05-06 10:43:09
【问题描述】：

我正在尝试使用 ElementTree 解析 XML 文件，并且在某些时候我只得到第一个孩子而不是标签内的所有孩子-以下是我的 XML 结构：-

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <sentences>
        <sentence id="2339">
            <text>I charge it at night and skip taking the cord with me because of the good battery life.</text>
            <aspectTerms>
                <aspectTerm term="cord" polarity="neutral" from="41" to="45"/>
                <aspectTerm term="battery life" polarity="positive" from="74" to="86"/>
            </aspectTerms>
        </sentence>
        <sentence id="812">
            <text>I bought a HP Pavilion DV4-1222nr laptop and have had so many problems with the computer.</text>
        </sentence>
        <sentence id="1316">
            <text>The tech guy then said the service center does not do 1-to-1 exchange and I have to direct my concern to the "sales" team, which is the retail shop which I bought my netbook from.</text>
            <aspectTerms>
                <aspectTerm term="service center" polarity="negative" from="27" to="41"/>
                <aspectTerm term="&quot;sales&quot; team" polarity="negative" from="109" to="121"/>
                <aspectTerm term="tech guy" polarity="neutral" from="4" to="12"/>
            </aspectTerms>
        </sentence>
    </sentences>

我想在每个“aspectTerm”标签中获取“term”。以下是我的代码：-

    import xml.etree.ElementTree as ET
    tree = ET.parse('Laptops_Train.xml')
    root = tree.getroot()
    df = pd.DataFrame()

    def getAspect(sentences):
        reviewList = []
        text = sentence.find('text').text
        reviewList.append(text)
        for aspectTerms in sentence.iter('aspectTerms'):
            #for aspectTerm in aspectTerms.iter('aspectTerm'): 
            aspect = aspectTerms.find('aspectTerm').get('term')
            print(aspect)
            return aspect

    aspectList = []
    for sentences in root.iter('sentences'):
        for sentence in sentences.iter('sentence'):
            aspectList.append(getAspect(sentence))

实际结果：

cord
class 'NoneType'
service center

预期结果：

[cord, battery life]
[]
[service center,&quot;sales&quot; team, tech guy]

提前致谢

【问题讨论】：

标签： xml python-3.x elementtree

【解决方案1】：

使用具有 xpath 的 lxml 库更容易做到这一点。

>>> from lxml import etree
>>> tree = etree.parse('Laptops_Train.xml')
>>> for aspectTerms in tree.xpath('.//aspectTerms'):
...     aspectTerms.xpath('aspectTerm/@term')
... 
['cord', 'battery life']
['service center', '"sales" team', 'tech guy']

还要注意所有aspectTerms 都有一个Term 属性；没有空的会产生None。

编辑，灵感来自评论。

>>> from lxml import etree
>>> tree = etree.parse('Laptops_Train.xml')
>>> for sentence in tree.xpath('.//sentence'):
...     sentence.xpath('.//aspectTerm/@term')
... 
['cord', 'battery life']
[]
['service center', '"sales" team', 'tech guy']

【讨论】：

非常感谢您的回答。您的解决方案要容易得多，但是当没有 aspectTerm 标签时，我必须插入空字符串。但毫无疑问，你做这项工作的方式要容易得多，但它不符合我的要求

【解决方案2】：

所以解决方案是使用 '.findall' 而不是 .find。因为 '.findall' 选择了所有的孩子。我的解决方案如下：-

    def getAspect(sentences):
        aspectList = []
        reviewList = []
        text = sentence.find('text').text
        reviewList.append(text)
        for aspectTerms in sentence.iter('aspectTerms'):
            #for aspectTerm in aspectTerms.iter('aspectTerm'): 
            aspect = aspectTerms.findall('aspectTerm')#.get('term')
            for aspectElem in aspect:
                aspects = aspectElem.get('term')
                aspectList.append(aspects)
                print(aspects)
        return aspectList


    aspectList = []
    for sentences in root.iter('sentences'):
        for sentence in sentences.iter('sentence'):
            aspectList.append(getAspect(sentence))

【讨论】：