Python:XPath 在 ElementTree 中不可用

2022-01-10 00:00:00 python python-2.7 elementtree xml-parsing iterparse

问题描述

我正在尝试使用 ElementTree 的 iterparse() 解析 iTunes 播放列表，但出现以下错误:

I am trying to parse iTunes Playlist by using iterparse() of ElementTree but getting following error:

AttributeError: 'Element' object has no attribute 'xpath'

代码如下:

import xml.etree.ElementTree as ET
context = ET.iterparse(file,events=("start", "end"))
    # turn it into an iterator
    context = iter(context)
    # get the root element
    event, root = context.next()
    for event, elem in context:
        z = elem.xpath(".//key")
        elem.clear()
        root.clear()
    print z

我做错了什么?文件太大，所以我必须使用 iterparse().

What I am doing wrong? File is too big so I have to use iterparse() anyway.

解决方案

xml.etree.ElementTree 对 XPath 表达式提供有限的支持 为其 Element 类 查找，findall 和 findtext 方法(没有 xpath 方法:这就是您收到错误的原因).

xml.etree.ElementTree provides limited support for XPath expressions for its Element class find, findall and findtext methods (there's no xpath method: that's why you are getting an error).

此外，如果您在元素上调用 clear() 以节省使用的内存，则只需在完成处理该元素及其所有元素之后 执行此操作孩子们.

Also, if you call clear() on an element to conserve used memory, you need to do it only after you've finished processing the element and all its children.

因此，您需要将代码更改为类似于以下内容:

Therefore, you need to to change your code to something similar to the following:

for event, elem in context:
    for child in elem.findall(".//key"):
        # process child
    elem.clear()
    root.clear()

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