<?
                xml version="1.0" encoding="utf-8"
                ?>
                <
                catalog
                >
                <
                maxid
                >4</maxid><login username="pytest" passwd=‘123456‘><caption>Python</caption><item id="4"><caption>测试</caption></item></login><item id="2"><caption>Zope</caption></item></catalog>

                #
                coding=utf-8
                #
                通过minidom解析xml文件
                import
                 xml.dom.minidom as xmldom

                import
                 os

                ‘‘‘
                 
XML文件读取 
<?xml version="1.0" encoding="utf-8"?>
<catalog>
    <maxid>4</maxid>
    <login username="pytest" passwd=‘123456‘>dasdas
        <caption>Python</caption>
        <item id="4">
            <caption>测试</caption>
        </item>
    </login>
    <item id="2">
        <caption>Zope</caption>
    </item>
</catalog>


                ‘‘‘
                

xmlfilepath = os.path.abspath("test.xml")
print ("xml文件路径：", xmlfilepath)

# 得到文档对象
domobj = xmldom.parse(xmlfilepath)
print("xmldom.parse:", type(domobj))
# 得到元素对象
elementobj = domobj.documentElement
print ("domobj.documentElement:", type(elementobj))

#获得子标签
subElementObj = elementobj.getElementsByTagName("login")
print ("getElementsByTagName:", type(subElementObj))

print (len(subElementObj))
# 获得标签属性值print (subElementObj[0].getAttribute("username"))
print (subElementObj[0].getAttribute("passwd"))

#区分相同标签名的标签
subElementObj1 = elementobj.getElementsByTagName("caption")
for i in range(len(subElementObj1)):
    print ("subElementObj1[i]:", type(subElementObj1[i]))
    print (subElementObj1[i].firstChild.data)  #显示标签对之间的数据

>>> D:\Pystu>python xml_instance.py
>>> xml文件路径： D:\Pystu\test.xml
>>> xmldom.parse: <class‘xml.dom.minidom.Document‘>
>>> domobj.documentElement: <class‘xml.dom.minidom.Element‘>
>>> getElementsByTagName: <class‘xml.dom.minicompat.NodeList‘>
>>> username: pytest
>>> passwd: 123456
>>> subElementObj1[i]: <class‘xml.dom.minidom.Element‘>
>>> Python
>>> subElementObj1[i]: <class‘xml.dom.minidom.Element‘>
>>> 测试
>>> subElementObj1[i]: <class‘xml.dom.minidom.Element‘>
>>> Zope

                #
                coding=utf-8
                #
                通过解析xml文件
                ‘‘‘
                
try:
    import xml.etree.CElementTree as ET
except:
    import xml.etree.ElementTree as ET

从Python3.3开始ElementTree模块会自动寻找可用的C库来加快速度    

                ‘‘‘
                import
                 xml.etree.ElementTree as ET

                import
                 os

                import
                 sys

                ‘‘‘
                 
XML文件读取 
<?xml version="1.0" encoding="utf-8"?>
<catalog>
    <maxid>4</maxid>
    <login username="pytest" passwd=‘123456‘>dasdas
        <caption>Python</caption>
        <item id="4">
            <caption>测试</caption>
        </item>
    </login>
    <item id="2">
        <caption>Zope</caption>
    </item>
</catalog>

                ‘‘‘
                #
                遍历xml文件
                def
                 traverseXml(element):
    
                #
                print (len(element))
                if len(element)>0:
        for child in element:
            print (child.tag, "----", child.attrib)
            traverseXml(child)
    #else:#print (element.tag, "----", element.attrib)if__name__ == "__main__":
    xmlFilePath = os.path.abspath("test.xml")
    print(xmlFilePath)
    try:
        tree = ET.parse(xmlFilePath)
        print ("tree type:", type(tree))
    
        # 获得根节点
        root = tree.getroot()
    except Exception as e:  #捕获除与程序退出sys.exit()相关之外的所有异常print ("parse test.xml fail!")
        sys.exit()
    print ("root type:", type(root))    
    print (root.tag, "----", root.attrib)
    
    #遍历root的下一层for child in root:
        print ("遍历root的下一层", child.tag, "----", child.attrib)

    #使用下标访问print (root[0].text)
    print (root[1][1][0].text)

    print (20 * "*")
    #遍历xml文件    traverseXml(root)
    print (20 * "*")

    #根据标签名查找root下的所有标签
    captionList = root.findall("item")  #在当前指定目录下遍历print (len(captionList))
    for caption in captionList:
        print (caption.tag, "----", caption.attrib, "----", caption.text)

    #修改xml文件，将passwd修改为999999
    login = root.find("login")
    passwdValue = login.get("passwd")
    print ("not modify passwd:", passwdValue)
    login.set("passwd", "999999")   #修改，若修改text则表示为login.textprint ("modify passwd:", login.get("passwd"))
    

>>> D:\Pystu\test.xml
>>> tree type: <class‘xml.etree.ElementTree.ElementTree‘>
>>> root type: <class‘xml.etree.ElementTree.Element‘>
>>> catalog ---- {}
>>> 遍历root的下一层 maxid ---- {}
>>> 遍历root的下一层 login ---- {‘username‘: ‘pytest‘, ‘passwd‘: ‘123456‘}
>>> 遍历root的下一层 item ---- {‘id‘: ‘2‘}
>>> 4
>>> 测试
>>> ********************
>>> maxid ---- {}
>>> login ---- {‘username‘: ‘pytest‘, ‘passwd‘: ‘123456‘}
>>> caption ---- {}
>>> item ---- {‘id‘: ‘4‘}
>>> caption ---- {}
>>> item ---- {‘id‘: ‘2‘}
>>> caption ---- {}
>>> ********************
>>> 1
>>> item ---- {‘id‘: ‘2‘} ----

>>> not modify passwd: 123456
>>> modify passwd: 999999