无法提取XML中所有<sequence-number>标签文本的问题求助

你的代码找不到标签的核心原因是XML命名空间不匹配：<sequence-number>属于http://cisco.com/ns/yang/Cisco-IOS-XR-ipv4-acl-cfg这个命名空间，直接用标签名查找会因为lxml默认不识别未声明的命名空间而返回空结果。

以下是两种可行的解决方法：

方法一：使用命名空间映射（推荐） #

通过定义命名空间前缀，在XPath中明确指定标签所属的命名空间：

#!/usr/bin/env python
from lxml import etree 

response = '''
<rpc-reply xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="urn:uuid:0d07cdf5-c8e5-45d9-89d1-92467ffd7fe4">
 <data>
  <ipv4-acl-and-prefix-list xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ipv4-acl-cfg">
   <accesses>
    <access>
     <access-list-name>TESTTEST</access-list-name>
     <access-list-entries>
      <access-list-entry>
       <sequence-number>1</sequence-number>
       <remark>TEST</remark>
       <sequence-str>1</sequence-str>
      </access-list-entry>
      <access-list-entry>
       <sequence-number>10</sequence-number>
       <grant>permit</grant>
       <source-network>
        <source-address>10.10.5.0</source-address>
        <source-wild-card-bits>0.0.0.255</source-wild-card-bits>
       </source-network>
       <next-hop>
        <next-hop-type>regular-next-hop</next-hop-type>
        <next-hop-1>
         <next-hop>10.10.5.2</next-hop>
         <vrf-name>SANE</vrf-name>
        </next-hop-1>
       </next-hop>
       <sequence-str>10</sequence-str>
      </access-list-entry>
      <access-list-entry>
       <sequence-number>20</sequence-number>
       <grant>permit</grant>
       <source-network>
        <source-address>10.10.6.0</source-address>
        <source-wild-card-bits>0.0.0.255</source-wild-card-bits>
       </source-network>
       <next-hop>
        <next-hop-type>regular-next-hop</next-hop-type>
        <next-hop-1>
         <next-hop>10.10.6.2</next-hop>
         <vrf-name>VRFNAME</vrf-name>
        </next-hop-1>
       </next-hop>
       <sequence-str>20</sequence-str>
      </access-list-entry>
     </access-list-entries>
    </access>
   </accesses>
  </ipv4-acl-and-prefix-list>
 </data>
</rpc-reply>
'''
q = etree.fromstring(response)
# 定义命名空间映射，前缀可自定义
ns_map = {'cisco': 'http://cisco.com/ns/yang/Cisco-IOS-XR-ipv4-acl-cfg'}
# 用带命名空间的XPath查找所有sequence-number标签
seq_nodes = q.findall('.//cisco:sequence-number', namespaces=ns_map)
# 提取每个标签的文本并转为列表
seq_numbers = [node.text for node in seq_nodes]
print(seq_numbers)  # 输出: ['1', '10', '20']

方法二：忽略命名空间（临时应急） #

如果不需要区分命名空间，可通过local-name()匹配标签名，但这种方法可能误匹配其他命名空间下的同名标签，仅适合简单场景：

seq_nodes = q.findall('.//*[local-name()="sequence-number"]')
seq_numbers = [node.text for node in seq_nodes]
print(seq_numbers)

内容的提问来源于stack exchange，提问作者Dave