在 python 中评估 Xpath2.0 [英] Evaluate Xpath2.0 in python
问题描述
我有一个 XPath 表达式，如下所示.
I have an XPath expression as shown below.
if(replace(//p[1]/text(),'H','h') = 'hello') then //p[1]/text() else if(//p[1]/text() = 'world') then //p[2]/text() else 'notFound'
我想显示哪个if"表达式有效.
I want to display which 'if ' expression worked.
e.g //p[1]/text() if first 'if' expression worked.
'If' 表达式可以嵌套 if、for 循环和 xpath2.0 函数.
'If' expression can have nested if, for loops and xpath2.0 functions.
我找不到任何适用于 python 的 xpath2.0 库.所以我尝试将此 Js library 转换为 python 仍然可以将 xpath2.0 表达式拆分为词法分析器，但无法将其完全转换为 python.
I can't find any xpath2.0 library for python. So I tried to convert this Js library to python still I can able to split xpath2.0 expression to lexers but can't convert it fully to python.
建议我一些适用于 python 的 Xpath2.0 库，如果有的话.还有如何解释 XPath 表达式并显示表达式的哪一部分有效?
Suggest me some Xpath2.0 library for python, if available. Also how to interpret XPath expression and display which part of the expression worked?
推荐答案
如您所知，lxml，Python 的 XML/XPath 支持的基石，只有特性
As you already know, lxml, the cornerstone of Python's XML/XPath support, features only
XPath 1.0、XSLT 1.0 和 EXSLT 扩展(通过 libxml2 和 libxslt)
XPath 1.0, XSLT 1.0 and the EXSLT extensions through libxml2 and libxslt
我们还有一些选择.
我最近研究了这个话题(特别是 Python 的 XQuery 支持).
请参阅 W3C 以获取 XML 查询实现的参考列表.
I researched this topic recently (specifically, Python's XQuery support).
See the W3C for a reference list of XML Query Implementations.
带有 XPath 2+ 和 EXSLT 扩展的 Python 模块(例如 EXSLT 用于正则表达式 matching)
PiPy 上的一些模块 部分提供了 XPath 2.0+ 功能.
Python Modules with XPath 2+ and EXSLT Extensions (e.g. an EXSLT for regex matching)
There are some modules on PiPy that partially offer XPath 2.0+ functionality.
有一些 OSS XML/NoSQL-DBMS 实现了 XPath/XQuery 2.0 功能，例如
There are some OSS XML/NoSQL-DBMS that implement XPath/XQuery 2.0 functions, e.g.
- Zorba，XQuery 1.0/2.0 的开源可移植嵌入式 C++ 实现，具有 Python 绑定(这个问题有一些提示)，
- 以及 Sedna 和一些商业 DBMS.根据您的项目，这可能是一个不错的选择.
- Zorba, an open source portable embeddable C++ implementation of XQuery 1.0/2.0 which has Python bindings (this question has some pointers),
- as well as Sedna and some commercial DBMS. Depending on your project, this could be a good choice.
我相信 Saxon/C(来自 Michael Kay) 与 Cython 是最有前途的道路.
在使用 Boost.Python 和 pysaxon.
更新:适用于 Python 3 的 Saxon/C 扩展同时发布.
I believe Saxon/C (by Michael Kay) with Cython is the most promising road.
It was tried before using Boost.Python and at pysaxon.
Update: A Saxon/C extension for Python 3 has been published meanwhile.
您可以使用子进程调用 CLI XML 处理器(如此处的建议)，例如subprocess.call(["saxon", "-o:output.xml", "-s:file.xml", "file.xslt"])
You could use a subprocess to call a CLI XML processor (as suggested here), e.g. subprocess.call(["saxon", "-o:output.xml", "-s:file.xml", "file.xslt"])
另一种选择是将 XSLT/XPath/XQuery 与撒克逊和/或其他Java XML 类 在 Jython.
Another option is using XSLT/XPath/XQuery with saxon and/or other Java XML classes in Jython.
最后，您可以设置一个 Web 服务，用 Java、.NET 等语言为您完成繁重的工作，并提供适当的 XPath 3+ 支持(也由 Kay 此处).
Finally, you could set-up a web service that does the hard work for you in a language like Java, .NET, etc, that comes with proper XPath 3+ support (also suggested by Kay here).
还是有些令人失望，尤其是对于像 Python 这样的大语言.
Still somewhat disappointing, especially for a big language like Python.
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