Python之xml学习笔记

XML处理模块 

 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，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 updated_by="yunfei">2009</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
        <info>
            <population>90</population>
            <size>960</size>
        </info>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated_by="yunfei">2012</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year updated_by="yunfei">2012</year>
        <gdppc>13600</gdppc>
        <neighbor direction="W" name="Costa Rica" />
        <neighbor direction="E" name="Colombia" />
    </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 #引用方法，重命名为ET

tree = ET.parse("xmltest.xml")
root = tree.getroot()
#print(root)
print(root.tag)#tag就是标签名<data>

# 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#转为int型后加1
    node.text = str(new_year)
    node.set("updated_by", "yunfei")#加一个属性

tree.write("xmltest.xml")

# 删除node
for country in root.findall('country'):#找出所有的country，循环country
    rank = int(country.find('rank').text)#找出country下的rank的text
    if rank > 50:
        root.remove(country)#移除此country

tree.write('output.xml')#结果放在output.xml里

创建xml文件：

import xml.etree.ElementTree as ET

new_xml = ET.Element("personinfolist")
personinfo = ET.SubElement(new_xml, "personinfo", attrib={"enrolled": "yes"})
name = ET.SubElement(personinfo, "name")
age = ET.SubElement(personinfo, "age", attrib={"checked": "no"})
sex = ET.SubElement(personinfo, "sex")
name.text='yunfei'
age.text = '24'
sex.text='男'

personinfo2 = ET.SubElement(new_xml, "personinfo2", attrib={"enrolled": "no"})
name = ET.SubElement(personinfo2, "name")
age = ET.SubElement(personinfo2, "age")
name.text='yuxia'
age.text = '19'
sex.text='女'

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

注：这是一篇学习笔记，大家多多指教。