xml.etree的特点

创建一个XML文档

通过构建代表XML树的元素的对象并将它们附加到根元素，可以生成XML文档。 这是如何创建XML数据的示例：

import xml.etree.ElementTree as ET

# Create a root element 
root = ET.Element("catalog")

# Create a book element as a child of the root
book1 = ET.SubElement(root, "book")
book1.set("id", "1")

# Add child elements to the book
title1 = ET.SubElement(book1, "title")
title1.text = "Python Programming"

author1 = ET.SubElement(book1, "author")
author1.text = "John Smith"

# Create another book element
book2 = ET.SubElement(root, "book")
book2.set("id", "2")

# Add child elements to the second book
title2 = ET.SubElement(book2, "title")
title2.text = "Data Science Essentials"

author2 = ET.SubElement(book2, "author")
author2.text = "Jane Doe"

# Create an ElementTree object from the root element
tree = ET.ElementTree(root)

import xml.etree.ElementTree as ET

# Create a root element 
root = ET.Element("catalog")

# Create a book element as a child of the root
book1 = ET.SubElement(root, "book")
book1.set("id", "1")

# Add child elements to the book
title1 = ET.SubElement(book1, "title")
title1.text = "Python Programming"

author1 = ET.SubElement(book1, "author")
author1.text = "John Smith"

# Create another book element
book2 = ET.SubElement(root, "book")
book2.set("id", "2")

# Add child elements to the second book
title2 = ET.SubElement(book2, "title")
title2.text = "Data Science Essentials"

author2 = ET.SubElement(book2, "author")
author2.text = "Jane Doe"

# Create an ElementTree object from the root element
tree = ET.ElementTree(root)

将XML文档写入文件

可以使用ElementTree对象的write()函数将XML文件写入文件：

# Write XML document to file
tree.write("catalog.xml")

# Write XML document to file
tree.write("catalog.xml")

这将在名为“catalog.xml”的文件中创建一个XML文档。

解析XML文档

ElementTree使用parse()函数解析XML数据：

# Parse an XML document
tree = ET.parse("catalog.xml")
root = tree.getroot()

# Parse an XML document
tree = ET.parse("catalog.xml")
root = tree.getroot()

这将解析XML文档“catalog.xml”，产生XML树的根元素。

访问元素和属性

使用Element对象提供的各种方法和属性，可以访问XML文档的元素和属性。 例如，查看第一本书的标题：

# Access the title of the first book
first_book_title = root[0].find("title").text
print("Title of the first book:", first_book_title)

# Access the title of the first book
first_book_title = root[0].find("title").text
print("Title of the first book:", first_book_title)

修改XML文档

通过添加、修改或删除组件和属性，可以更改XML文档。 比如要改变第二本书的作者：

# Modify the author of the second book
root[1].find("author").text = "Alice Smith"

# Modify the author of the second book
root[1].find("author").text = "Alice Smith"

序列化XML文档

可以使用ElementTree模块的tostring()函数将XML文档序列化为字符串：

# Serialize XML document to string
xml_string = ET.tostring(root, encoding="unicode")
print(xml_string)

# Serialize XML document to string
xml_string = ET.tostring(root, encoding="unicode")
print(xml_string)