python的xml模块用法

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:

<?xml version="1.0"?>
    <data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>

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 　

　

    import xml.etree.ElementTree as ET

    tree = ET.parse("xmltest.xml")
    root = tree.getroot()
    print(root.tag)

    #遍历xml文档
    for child in root:
    print(child.tag, child.attrib)
    for i in child:
        print(i.tag,i.text)

    #只遍历year 节点
    for node in root.iter('year'):
    print(node.tag,node.text)

修改和删除xml文档内容

import xml.etree.ElementTree as ET

    tree = ET.parse("xmltest.xml")
    root = tree.getroot()

    #修改
    for node in root.iter('year'):
    new_year = int(node.text) + 1
    node.text = str(new_year)
    node.set("updated","yes")

    tree.write("xmltest.xml")

    #删除node
    for country in root.findall('country'):
       rank = int(country.find('rank').text)
       if rank > 50:
         root.remove(country)

    tree.write('output.xml')

自己创建xml文档

import xml.etree.ElementTree as ET

    new_xml = ET.Element("namelist")
    name = ET.SubElement(new_xml,"name",attrib={"enrolled":"yes"})
    age = ET.SubElement(name,"age",attrib={"checked":"no"})
    sex = ET.SubElement(name,"sex")
    sex.text = '33'
    name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})
    age = ET.SubElement(name2,"age")
    age.text = '19'

    et = ET.ElementTree(new_xml) #生成文档对象
    et.write("test.xml", encoding="utf-8",xml_declaration=True)

    ET.dump(new_xml) #打印生成的格式