22.XML

转载：https://www.cnblogs.com/yuanchenqi/article/5732581.html

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数据

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)
#---------------------------------------

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 = ''
name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})
age = ET.SubElement(name2,"age")
age.text = ''

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

 DEMO

import  xml.etree.ElementTree as ET
# 创建
'''
<?xml version='1.0' encoding='utf-8'?>
<peoples>
    <people show="yes">
        <name show="yes">ray</name>
        <age show="yes">22</age>
        <sex show="yes">male</sex>
    </people>
</peoples>
'''
new_xml = ET.Element("peoples")
people = ET.SubElement(new_xml,"people",attrib={"show":"yes"})
name = ET.SubElement(people,"name",attrib={"show":"yes"})
age = ET.SubElement(people,"age",attrib={"show":"yes"})
sex = ET.SubElement(people,"sex",attrib={"show":"yes"})
name.text = 'ray'
age.text = ''
sex.text = 'male'
et = ET.ElementTree(new_xml)
et.write("test1.xml", encoding="utf-8", xml_declaration=True)
ET.dump(new_xml)

# 操作
tree = ET.parse('test1.xml')
root = tree.getroot()
# 修改
# for node in root.iter('age'):
#     new_age = int(node.text)+1
#     node.text = str(new_age)
#     node.set('updated','yes')
# tree.write('test1.xml')
# 删除
# for people in root.findall('people'):
#     name = people.find('name').text
#     if(name == 'ray'):
#         root.remove(people)
# tree.write('test1.xml')