python - 使用 xpath 匹配第一组元素

Question

我有一个如下所示的 xml 文档。

<foo>
    <bar type="artist"/> Bob Marley </bar>
    <bar type="artist"/> Peter Tosh </bar>
    <bar type="artist"/> Marlon Wayans </bar>
</foo>
<foo>
    <bar type="artist"/> Bob Marley </bar>
    <bar type="artist"/> Peter Tosh </bar>
    <bar type="artist"/> Marlon Wayans </bar>
</foo>
<foo>
    <bar type="artist"/> Bob Marley </bar>
    <bar type="artist"/> Peter Tosh </bar>
    <bar type="artist"/> Marlon Wayans </bar>
</foo>

我想构造一个仅返回第一组的 xpath:

<bar type="artist"/> Bob Marley </a>
<bar type="artist"/> Peter Tosh </a>
<bar type="artist"/> Marlon Wayans </a>

如何解决这个问题？我已经尝试过 //bar[@type='artist'] 但显然还有更多内容。提前致谢。

Answer 1

为了仅获取某些“索引”节点的子元素:

//foo[1]/bar[@type='artist']

C# 示例:

string xml =
    @"<root>
        <foo>
            <bar type='artist'> Artist 1 </bar>
            <bar type='artist'> Artist 2 </bar>
            <bar type='artist'> Artist 3 </bar>
        </foo>
        <foo>
            <bar type='artist'> Artist 1 </bar>
            <bar type='artist'> Artist 2 </bar>
            <bar type='artist'> Artist 3 </bar>
            <bar type='artist'> Artist 4 </bar>
        </foo>
    </root>";
XmlDocument document = new XmlDocument();
document.LoadXml(xml);

Assert.That(document.SelectNodes(@"/root/foo[1]/bar[@type='artist']").Count,
                                 Is.EqualTo(3));
Assert.That(document.SelectNodes(@"//foo[1]/bar[@type='artist']").Count,
                                 Is.EqualTo(3));