如何在python中使用xpath列出屬性值

Question

我使用下面的python代碼做xpath屬性查找，但得到一個錯誤：
selector.append（ops [token [0]]（next，token ）） KeyError異常： '@'
只是用starndard python2.7版本，沒有額外的模塊

的xml文件看起來像：

<rule-set> 
<rule name="firstRule" salience="3" /> 
<rule name="secondRule" salience="5" /> 
</rule-set> 

我的代碼如下所示：

import xml.etree.ElementTree as ET 
fp = open("./rules.xml", "r") 
elementTree = ET.parse(fp) 
e = elementTree.findall('rule') #looking up element, this works 
for i in e: 
    print i.attrib 
e = elementTree.findall('rule/@salience') #directly looking up attribute fails 
for i in e: 
    print i 
print 'all done' 

我有點困惑，...我認爲這個xpath查找將支持xpath1.0，或者我做錯了什麼？

Answer 1

從docs

This module provides limited support for XPath expressions for locating elements in a tree. The goal is to support a small subset of the abbreviated syntax; a full XPath engine is outside the scope of the module.

的xml.etree模塊不允許直接使用它的xpath syntax，只選擇具有某些屬性的元素選擇屬性。

如果您想要更完整的xpath支持，您應該查看lxml。 etree