【python】lxml中多個xml采用相同節點時出現的問題

今天突然發現了一個lxml的坑。

假設我們有一個節點

<id>123</id>

有兩個父節點都要用上述節點，則必須把上面的節點寫兩遍！用同一個會出錯！

 

出錯例子：

#!/usr/bin/env python
#encoding:utf8

from lxml import etree

if __name__ == "__main__":
    
    root1 = etree.Element("root1")  #根節點1
    root2 = etree.Element("root2")  #根節點2
    ver_node = etree.Element("id")  #子節點
    ver_node.text = "123"
    
    root1.append(ver_node)  #都加入了同一個子節點
    root2.append(ver_node)
    
    print etree.tostring(root1, pretty_print=True, xml_declaration=True, encoding='UTF-8')
    print etree.tostring(root2, pretty_print=True, xml_declaration=True, encoding='UTF-8')

結果：

<?xml version='1.0' encoding='UTF-8'?>
<root1/>

<?xml version='1.0' encoding='UTF-8'?>
<root2>
  <id>123</id>
</root2>

只有后面一個有子節點，前面一個沒有！

 

 

正確寫法：

#!/usr/bin/env python
#encoding:utf8
from lxml import etreeimport copy

if __name__ == "__main__":
    root1 = etree.Element("root1")
    root2 = etree.Element("root2")
    ver_node1 = etree.Element("id")
    ver_node1.text = "123"
    ver_node2 = copy.deepcopy(ver_node1) #深拷貝！
    
    root1.append(ver_node1)
    root2.append(ver_node2)
    
    print etree.tostring(root1, pretty_print=True, xml_declaration=True, encoding='UTF-8')
    print etree.tostring(root2, pretty_print=True, xml_declaration=True, encoding='UTF-8')

結果：

<?xml version='1.0' encoding='UTF-8'?>
<root1>
  <id>123</id>
</root1>

<?xml version='1.0' encoding='UTF-8'?>
<root2>
  <id>123</id>
</root2>