Python XPath 语法错误 : invalid predicate

Question

我正在尝试像这样解析一个 xml

<document>
    <pages>

    <page>   
       <paragraph>XBV</paragraph>

       <paragraph>GHF</paragraph>
    </page>

    <page>
       <paragraph>ash</paragraph>

       <paragraph>lplp</paragraph>
    </page>

    </pages>
</document>

这是我的代码

import xml.etree.ElementTree as ET

tree = ET.parse("../../xml/test.xml")

root = tree.getroot()

path="./pages/page/paragraph[text()='GHF']"

print root.findall(path)

但是我得到一个错误

print root.findall(path)
  File "X:\Anaconda2\lib\xml\etree\ElementTree.py", line 390, in findall
    return ElementPath.findall(self, path, namespaces)
  File "X:\Anaconda2\lib\xml\etree\ElementPath.py", line 293, in findall
    return list(iterfind(elem, path, namespaces))
  File "X:\Anaconda2\lib\xml\etree\ElementPath.py", line 263, in iterfind
    selector.append(ops[token[0]](next, token))
  File "X:\Anaconda2\lib\xml\etree\ElementPath.py", line 224, in prepare_predicate
    raise SyntaxError("invalid predicate")
SyntaxError: invalid predicate

我的 xpath 有什么问题？

跟进

谢谢 faltru，您的解决方案奏效了。我有跟进。现在，我想获取文本 GHF 段落之前的所有段落元素。所以在这种情况下，我只需要 XBV 元素。我想忽略 ash 和 lplp。我想这样做的一种方法是

result = []
for para in root.findall('./pages/page/'):
    t = para.text.encode("utf-8", "ignore")
    if t == "GHF":
       break
    else:
        result.append(para)

但是有更好的方法吗？

Answer 1

ElementTree's XPath support is limited.使用其他库，如 lxml :

import lxml.etree
root = lxml.etree.parse('test.xml')

path="./pages/page/paragraph[text()='GHF']"
print root.xpath(path)