Python(xml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_test文件，xml格式。

 1 <?xml version="1.0"?>
 2 <data>
 3     <country name="Liechtenstein">
 4         <rank updated="yes">2</rank>
 5         <year>2008</year>
 6         <gdppc>141100</gdppc>
 7         <neighbor name="Austria" direction="E"/>
 8         <neighbor name="Switzerland" direction="W"/>
 9     </country>
10     <country name="Singapore">
11         <rank updated="yes">5</rank>
12         <year>2011</year>
13         <gdppc>59900</gdppc>
14         <neighbor name="Malaysia" direction="N"/>
15     </country>
16     <country name="Panama">
17         <rank updated="yes">69</rank>
18         <year>2011</year>
19         <gdppc>13600</gdppc>
20         <neighbor name="Costa Rica" direction="W"/>
21         <neighbor name="Colombia" direction="E"/>
22     </country>
23 </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：

 1 import xml.etree.ElementTree as ET
 2 
 3 tree = ET.parse("xml_test")
 4 root = tree.getroot()
 5 print(root.tag)#根标签
 6 
 7 
 8 print("\n")
 9 #遍历xml文档
10 for child in root:#遍历child
11     print(child.tag, child.attrib)#标签，属性
12 
13 print("\n")
14 #遍历xml文档
15 for child in root:#遍历child
16     #print(child.tag, child.attrib)#标签，属性
17     for i in child:#遍历child中内容
18         print(i.tag,i.text) #neighbor是None,因为它是自闭合标签

执行结果：

data


country {'name': 'Liechtenstein'}
country {'name': 'Singapore'}
country {'name': 'Panama'}


rank 2
year 2008
gdppc 141100
neighbor None
neighbor None
rank 5
year 2011
gdppc 59900
neighbor None
rank 69
year 2011
gdppc 13600
neighbor None
neighbor None

Process finished with exit code 0

neighbor是None,因为它是自闭合标签

 1 import xml.etree.ElementTree as ET
 2 
 3 tree = ET.parse("xml_test")
 4 root = tree.getroot()
 5 
 6 
 7 # 修改
 8 for node in root.iter('year'):
 9     new_year = int(node.text) + 1
10     node.text = str(new_year)
11     node.set("updated", "yes")
12 
13 tree.write("xml_test.xml")
14 
15 # 删除node
16 for country in root.findall('country'):#根里面找country标签
17     rank = int(country.find('rank').text)
18     if rank > 50:#50名开外的删除
19         root.remove(country)
20 
21 tree.write('output.xml')

修改xml_test文件，和删除其中节点。

创建xml

 1 import xml.etree.ElementTree as ET
 2  
 3  
 4 new_xml = ET.Element("namelist")
 5 name = ET.SubElement(new_xml,"name",attrib={"enrolled":"yes"})
 6 age = ET.SubElement(name,"age",attrib={"checked":"no"})
 7 sex = ET.SubElement(name,"sex")
 8 sex.text = '33'
 9 name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})
10 age = ET.SubElement(name2,"age")
11 age.text = '19'
12  
13 et = ET.ElementTree(new_xml) #生成文档对象
14 et.write("test.xml", encoding="utf-8",xml_declaration=True)
15  
16 ET.dump(new_xml) #打印生成的格式
17

生成test.xml

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

只需了解

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