Python全栈之路----常用模块----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，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("xml_test.xml") #open

root = tree.getroot() #f.seek(0)

print(root.tag)

#遍历xml文档

for child in root: #data 下一层的关键词country

    print(child.tag, child.attrib)

    print('----i start----')

    for i in child:

        print(i.tag,i.text)

    print('----i stop----')

#只遍历year 节点

print('----year----')

for node in root.iter('year'):

    print(node.tag,node.text)

运行结果

data

country {'name': 'Liechtenstein'}

----i start----

rank 2

year 2008

gdppc 141100

neighbor None

neighbor None

----i stop----

country {'name': 'Singapore'}

----i start----

rank 5

year 2011

gdppc 59900

neighbor None

----i stop----

country {'name': 'Panama'}

----i start----

rank 69

year 2011

gdppc 13600

neighbor None

neighbor None

----i stop----

----year----

year 2008

year 2011

year 2011

修改和删除xml文档

import xml.etree.ElementTree as ET

tree = ET.parse("xml_test.xml") #open

root = tree.getroot() #f.seek(0)

#修改

for node in root.iter('year'): #只从下一层里面找

    new_year = int(node.text) + 1

    node.text = str(new_year)

    node.set("attr_test","yes") #设置属性

tree.write("xmltest.xml")

#删除node

for country in root.findall('country'): #findall 找到所有的 country

   rank = int(country.find('rank').text)

   if rank > 50:

     root.remove(country)

tree.write('output.xml')

自己创建xml文件

import xml.etree.ElementTree as ET

root = ET.Element("namelist") #root

name = ET.SubElement(root,"name",attrib={"enrolled":"yes"})

age = ET.SubElement(name,"age",attrib={"checked":"no"})

sex = ET.SubElement(name,"sex")

sex.text = ''

name2 = ET.SubElement(root,"name",attrib={"enrolled":"no"})

age = ET.SubElement(name2,"age")

age.text = ''

et = ET.ElementTree(root) #生成文档对象

et.write("build_out.xml", encoding="utf-8", xml_declaration=True)

ET.dump(root) #打印生成的格式

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Python全栈之路----常用模块----xml处理模块

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