ho修复xpath的lxml

Question

有人可以向我解释为什么Xptah在Elementree上的功能在元素上失败时起作用。

1. 它正在工作

   导入lxml.etree作为et

   xml1 = et.parse（data1）

   xml1.xpath（“ ws：book [ws：frome_information/ws：book_on_av ='1'或“
   ） “ WS：第2章/WS：has_international_assignment ='false']/ws：第3章/ws：book_type /text（）“，namespace = namespace1）

- 输出 - ['常规'，'常规']

2. 它不起作用

xp =” [ws：afre_information/ws：book_on_av ='1'或 ws：第3章/ws：book_type/text（）

for book in xml1.findall("ws:Book", namespaces=NAMESPACE1):
    print(book.xpath(xp, namespaces=NAMESPACE1))

WS：第2章/WS：has_international_assignment =' false

print(book.xpath(xp, namespaces=NAMESPACE1))
File "src\lxml\etree.pyx", line 1597, in lxml.etree._Element.xpath
File "src\lxml\xpath.pxi", line 305, in lxml.etree.XPathElementEvaluator.__call__
File "src\lxml\xpath.pxi", line 225, in lxml.etree._XPathEvaluatorBase._handle_result
lxml.etree.XPathEvalError: Invalid expression

'] /

<?xml version="1.0" encoding="UTF-8"?>
<ws:Books xmlns:ws="urn:com.aa/bb" >
    <ws:Book>enter code here
        <ws:Chapter1>
            <ws:Data>
                <ws:Type>Preferred</ws:Type>
                <ws:Book_Name>Book1</ws:Book_Name>
            </ws:Data>
        </ws:Chapter1>
        <ws:Chapter2>
            <ws:Has_International_Assignment>true</ws:Has_International_Assignment>
        </ws:Chapter2>
        <ws:Chapter3>
            <ws:Operation>ADD</ws:Operation>
            <ws:Book_Type ws:PriorValue="">Regular</ws:Book_Type>
        </ws:Chapter3>
        <ws:Additional_Information>
            <ws:Book_on_AV>1</ws:Book_on_AV>
        </ws:Additional_Information>
    </ws:Book>
    <ws:Book>
        <ws:Chapter1>
            <ws:Data>
                <ws:Type>Preferred</ws:Type>
                <ws:Book_Name>Book2</ws:Book_Name>
            </ws:Data>
        </ws:Chapter1>
        <ws:Chapter2>
            <ws:Has_International_Assignment>true</ws:Has_International_Assignment>
        </ws:Chapter2>
        <ws:Chapter3>
            <ws:Operation>ADD</ws:Operation>
            <ws:Book_Type ws:PriorValue="">Regular</ws:Book_Type>
        </ws:Chapter3>
        <ws:Additional_Information>
            <ws:Book_on_AV>1</ws:Book_on_AV>
        </ws:Additional_Information>
    </ws:Book>
</ws:Books>

Answer 1

您无法使用方括号中的谓词启动路径表达式，即以[不起作用的内部XPath表达式。我希望使用。[而不是使用LXML/XPATH 1.0测试）。如果。[给出错误，请尝试self :: WS：book [。