python

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，在以前，在json还没诞生之前，xml十分流行，

以至于到现在很多传统公司如金融行业的很多系统的接口还主要是xml。

#!/usr/bin/env python
#coding:utf-8


import xml.etree.ElementTree as ET

print(''' 
     =============打印根节点的名字============
    ''')
tree = ET.parse("./file/test.xml")    #指定要解析的xml文件
root = tree.getroot()   #根节点里面的所有内容
print(root.tag)      #打印xml文件根节点的名字,eg：./file/test.xml中的data

print(''' 
     =============遍历整个xml文档============
    ''')
#遍历xml文档   .tag:节点名   .attrib: 节点属性   .text: 节点内容
for child in root:      #打印根节点下的第一层子节点 country
    print(child.tag, child.attrib)
    for i in child:      #打印第一层子节点下的子节点（第二层子节点）
        print(i.tag,i.text)

print(''' 
     =============只遍历year 节点============
    ''')
#只遍历year 节点   
# root.iter('year'): 在./file/test.xml中选择出所有节点名为'year'的节点
# .iter('year')  返回一个迭代器包含所有匹配的元素。
for node in root.iter('year'):
    print(node.tag,node.text)

print('''
    =============修改xml文档============
''')
#修改xml文档，把所有year节点的值+1
for node in root.iter('year'):
    new_year = int(node.text) + 1
    node.text = str(new_year)
    node.set("updated","yes")    #给节点增加属性
 
tree.write("./file/test1.xml")   #对文档做修改后要进行写入，才能保存修改
print("修改结果看./file/test1.xml") 

print('''
    =============删除xml文档节点============
''')
#删除指定node
#for country in root.iter('country'):   可以有同样效果，原理不同
for country in root.findall('country'):
    print(country.tag,country.attrib)
    rank = int(country.find('rank').text)
    if rank > 50:
        root.remove(country)
 
tree.write('./file/test2.xml')    #对文档做修改后要进行写入，才能保存修改
print("删除后的结果看./file/test1.xml") 



print('=============创建xml文档============')

import xml.etree.ElementTree as ET

new_xml = ET.Element("namelist")  #定义根节点
name = ET.SubElement(new_xml,"name1",attrib={"enrolled":"yes"})
age = ET.SubElement(name,"age",attrib={"checked":"no"})
sex = ET.SubElement(name,"sex")
age.text = '33'
sex.text = 'male'
name2 = ET.SubElement(new_xml,"name2",attrib={"enrolled":"no"})
age = ET.SubElement(name2,"age")
sex = ET.SubElement(name2,"sex")
age.text = '19'
sex.text = 'female'

et = ET.ElementTree(new_xml) #生成文档对象
et.write("./file/test3.xml", encoding="utf-8",xml_declaration=True)

#ET.dump(new_xml) #打印生成的格式在屏幕

print('创建后结果看./file/test3.xml')

上面涉及到文件：

<?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>

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="yes">2009</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="yes">2012</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank> 
        <year updated="yes">2012</year>
        <gdppc>13600</gdppc>
        <neighbor direction="W" name="Costa Rica" />
        <neighbor direction="E" name="Colombia" />
    </country>
</data>

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="yes">2009</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="yes">2012</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
    </data>

<?xml version='1.0' encoding='utf-8'?>
<namelist><name1 enrolled="yes"><age checked="no">33</age><sex>male</sex></name1><name2 enrolled="no"><age>19</age><sex>female</sex></name2></namelist>