我嘗試使用lxml解析XML文件。它與一些文件，但最後一個給了我一個錯誤：Python lxml/XPathEvalError：解析xml文件時出現無效表達式

XPathEvalError at /admin/xml_exportation/xml/add/ 
Invalid expression

下面是XML代碼：

<?xml version="1.0" encoding="utf-8" ?> 
<export source="Source" version="1.0" date="2014-02-21T17:46:57"> 
    <Agence ID="XX1" externRef="XX1" customCode="38495"> 
    <Biens> 
     <Bien ID="XX1-176" ref="XX1-176"> 
     <DateMAJ>2013-06-14T12:12:07</DateMAJ> 
     </Bien> 
    </Biens> 
    </Agence> 
</export>

然後是Python代碼：

tree = etree.parse(xml_file) 
root_path = '/export/Agence/Biens/Bien/' 
for element in tree.xpath(root_path): 
    print(element)

我試着改變路徑，但它給了我同樣的錯誤。

謝謝您的幫助。

編輯

Internal Server Error: /admin/xml_exportation/xml/add/ 
Traceback (most recent call last): 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 115, in get_response 
    response = callback(request, *callback_args, **callback_kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 372, in wrapper 
    return self.admin_site.admin_view(view)(*args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view 
    response = view_func(request, *args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/views/decorators/cache.py", line 89, in _wrapped_view_func 
    response = view_func(request, *args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/sites.py", line 202, in inner 
    return view(request, *args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 25, in _wrapper 
    return bound_func(*args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 91, in _wrapped_view 
    response = view_func(request, *args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/utils/decorators.py", line 21, in bound_func 
    return func(self, *args2, **kwargs2) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/db/transaction.py", line 223, in inner 
    return func(*args, **kwargs) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 1007, in add_view 
    self.save_model(request, new_object, form, False) 
    File "/home/python-envs/website.com/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 740, in save_model 
    obj.save() 
    File "astucesexperts/apps/xml_exportation/models.py", line 154, in save 
    for element in tree.xpath(root_path): # Find each new property 
    File "lxml.etree.pyx", line 2115, in lxml.etree._ElementTree.xpath (src/lxml/lxml.etree.c:57669) 
    File "xpath.pxi", line 370, in lxml.etree.XPathDocumentEvaluator.__call__ (src/lxml/lxml.etree.c:146579) 
    File "xpath.pxi", line 238, in lxml.etree._XPathEvaluatorBase._handle_result (src/lxml/lxml.etree.c:144977) 
    File "xpath.pxi", line 224, in lxml.etree._XPathEvaluatorBase._raise_eval_error (src/lxml/lxml.etree.c:144832) 
XPathEvalError: Invalid expression

我也從一個XML文件，我可以用腳本（更改根路徑）導出添加代碼。

<?xml version='1.0' encoding='UTF-8' ?> 
<ANNONCES> 
    <ANNONCE> 
     <AGENCE_REF><![CDATA[22]]></AGENCE_REF> 
     <AGENCE_NOM><![CDATA[Agence]]></AGENCE_NOM> 
<REFERENCE><![CDATA[100lm]]></REFERENCE> 
     <TRANSACTION><![CDATA[2]]></TRANSACTION> 
     <TYPE><![CDATA[2]]></TYPE> 
     <SOUSTYPE><![CDATA[45]]></SOUSTYPE> 
     <SURFACE><![CDATA[100]]></SURFACE> 
    <ANNONCE> 
</ANNONCES>

來源

2014-09-30 pepourquier

這是有幫助的，包括回溯，所以我們知道哪一行導致了問題。 – tdelaney 2014-09-30 19:59:53

錯誤意味着xpath表達式'/ admin/xml_exportation/xml/add /'不好 - 尾隨的'/'是非法的。我認爲代碼崩潰在與您展示的地點不同的地方。 – tdelaney 2014-09-30 20:10:15

我用這個代碼與另一個xml文件，它的工作。這就是爲什麼我認爲崩潰來自xml和python。 – pepourquier 2014-10-01 05:03:04

您的XPath具有尾隨的'/'。刪除它，一切按預期工作。

也就是說，變化：

root_path = '/export/Agence/Biens/Bien/'

到

root_path = '/export/Agence/Biens/Bien'

來源

2014-10-01 05:50:30

爲<Biens>你關閉標籤沒有反斜槓，所以你的樹是空的，因爲XML沒有解析。

在嘗試使用Python解析它之前驗證您的XML。

來源

2014-09-30 19:58:01 ArunasR

寫這個問題可能只是一個錯誤。一個不匹配的標籤會拋出一個XMLSyntaxError。 – tdelaney 2014-09-30 20:04:35

感謝您的意見。是的，我寫這個問題只是一個錯誤。 – pepourquier 2014-10-01 04:50:12

Python lxml/XPathEvalError：解析xml文件時出現無效表達式

編輯

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