xml模块

一、xml简介

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:

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<?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>

二、Python使用xml

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：

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# print(root.iter('year')) #全文搜索 # print(root.find('country')) #在root的子节点找，只找一个 # print(root.findall('country')) #在root的子节点找，找所有 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, child.attrib['name']) for i in child: print(i.tag, i.attrib, 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') node.set('version', '1.0') tree.write('test.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') #在country内添加（append）节点year2 import xml.etree.ElementTree as ET tree = ET.parse("a.xml") root = tree.getroot() for country in root.findall('country'): for year in country.findall('year'): if int(year.text) > 2000: year2 = ET.Element('year2') year2.text = '新年' year2.attrib = {'update': 'yes'} country.append(year2) #往country节点下添加子节点 tree.write('a.xml.swap')

三、自己创建xml文档

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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 = '33' name2 = ET.SubElement(new_xml, "name", attrib={"enrolled": "no"}) age = ET.SubElement(name2, "age") age.text = '19' 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