xml 模块 - 图1

一、xml简介

xml是实现不同语言或程序之间进行数据交换的协议，跟json差不多，但json使用起来更简单，不过，古时候，在json还没诞生的黑暗年代，大家只能选择用xml呀，至今很多传统公司如金融行业的很多系统的接口还主要是xml。
xml的格式如下，就是通过<>节点来区别数据结构的:

  1. <?xml version="1.0"?>
  2. <data>
  3.     <country name="Liechtenstein">
  4.         <rank updated="yes">2</rank>
  5.         <year>2008</year>
  6.         <gdppc>141100</gdppc>
  7.         <neighbor name="Austria" direction="E"/>
  8.         <neighbor name="Switzerland" direction="W"/>
  9.     </country>
  10.     <country name="Singapore">
  11.         <rank updated="yes">5</rank>
  12.         <year>2011</year>
  13.         <gdppc>59900</gdppc>
  14.         <neighbor name="Malaysia" direction="N"/>
  15.     </country>
  16.     <country name="Panama">
  17.         <rank updated="yes">69</rank>
  18.         <year>2011</year>
  19.         <gdppc>13600</gdppc>
  20.         <neighbor name="Costa Rica" direction="W"/>
  21.         <neighbor name="Colombia" direction="E"/>
  22.     </country>
  23. </data>

二、Python使用xml

xml协议在各个语言里的都 是支持的，在python中可以用以下模块操作xml：

  1. # print(root.iter('year')) #全文搜索
  2. # print(root.find('country')) #在root的子节点找，只找一个
  3. # print(root.findall('country')) #在root的子节点找，找所有
  5. import xml.etree.ElementTree as ET
  7. tree = ET.parse("xmltest.xml")
  8. root = tree.getroot()
  9. print(root.tag)
  11. #遍历xml文档
  12. for child in root:
  13.     print('========>', child.tag, child.attrib, child.attrib['name'])
  14.     for i in child:
  15.         print(i.tag, i.attrib, i.text)
  17. #只遍历year 节点
  18. for node in root.iter('year'):
  19.     print(node.tag, node.text)
  20. #---------------------------------------
  22. import xml.etree.ElementTree as ET
  24. tree = ET.parse("xmltest.xml")
  25. root = tree.getroot()
  27. #修改
  28. for node in root.iter('year'):
  29.     new_year = int(node.text) + 1
  30.     node.text = str(new_year)
  31.     node.set('updated', 'yes')
  32.     node.set('version', '1.0')
  33. tree.write('test.xml')
  35. #删除node
  36. for country in root.findall('country'):
  37.     rank = int(country.find('rank').text)
  38.     if rank > 50:
  39.         root.remove(country)
  41. tree.write('output.xml')
  43. #在country内添加（append）节点year2
  44. import xml.etree.ElementTree as ET
  45. tree = ET.parse("a.xml")
  46. root = tree.getroot()
  47. for country in root.findall('country'):
  48.     for year in country.findall('year'):
  49.         if int(year.text) > 2000:
  50.             year2 = ET.Element('year2')
  51.             year2.text = '新年'
  52.             year2.attrib = {'update': 'yes'}
  53.             country.append(year2)  #往country节点下添加子节点
  55. tree.write('a.xml.swap')

三、自己创建xml文档

  1. import xml.etree.ElementTree as ET
  3. new_xml = ET.Element("namelist")
  4. name = ET.SubElement(new_xml, "name", attrib={"enrolled": "yes"})
  5. age = ET.SubElement(name, "age", attrib={"checked": "no"})
  6. sex = ET.SubElement(name, "sex")
  7. sex.text = '33'
  8. name2 = ET.SubElement(new_xml, "name", attrib={"enrolled": "no"})
  9. age = ET.SubElement(name2, "age")
  10. age.text = '19'
  12. et = ET.ElementTree(new_xml)  #生成文档对象
  13. et.write("test.xml", encoding="utf-8", xml_declaration=True)
  15. ET.dump(new_xml)  #打印生成的格式