Python基础之读写xml总结
参考文章：https://blog.csdn.net/weixin_42749767/article/details/82770563
https://www.cnblogs.com/Erick-L/p/6416379.html
两种读写xml的方式各有优势，看自己想要哪种功能。简单说下：
1. minidom创建的XML格式有缩进，好看。用ET创建的xml没有缩进空行等，用文本打开不好看。
2. minidom得到已知标签的所有节点比较容易，但是如果要是得到子节点就不太方便，因为空行和空格会被算作文本节点，那么对不同格式的xml可能得到的结果不同。ET获取子节点比较容易，也可使用相对路径或者xpath进行定位，操作更加灵活。
选用哪种xml库就看自己需求偏向于哪一种了。
一、用xml.dom.minidom写xml
a. 写XML使用范例：
writexml.py
#!/usr/bin/env python # _*_ coding: UTF-8 _*_ """================================================= @Project -> File : write_xml.py @IDE : PyCharm @Author : zihan @Date : 2021/10/15 13:28 @Desc : =================================================""" import xml.dom.minidom def writexml(): doc = xml.dom.minidom.Document() root = doc.createElement('BOOK') # 创建节点 root.setAttribute('Description', 'This is a book store') # 设置节点属性 root.setAttribute('Name', 'Happy Home') # 设置节点属性 doc.appendChild(root) # 添加根节点 book1 = doc.createElement('book') # 创建节点 book1.setAttribute('Name', 'C++') # 设置节点属性 book1_1 = doc.createElement('book') # 创建book1_1节点 book1_1.setAttribute('language', 'Chinese') # 设置节点属性 book1_1.appendChild(doc.createTextNode("C++从入门到精通")) # 设置节点的Value值。doc.createTextNode就是文本节点 book1_2 = doc.createElement('book') book1_2.setAttribute('language', 'Chinese') book1_2.appendChild(doc.createTextNode("C++程序设计语言")) book2 = doc.createElement('book') book2.setAttribute('Name', 'Python') book2_1 = doc.createElement('book') book2_1.setAttribute('language', 'Chinese') book2_1.appendChild(doc.createTextNode("Python从入门到精通")) book3 = doc.createElement('book') book3.setAttribute('Name', 'Linux') book3_1 = doc.createElement('book') book3_1.setAttribute('language', 'Chinese') book3_1.appendChild(doc.createTextNode("Linux从入门到精通")) book1.appendChild(book1_1) # book1节点添加子节点book1_1 book1.appendChild(book1_2) # book1节点添加子节点book1_2 book2.appendChild(book2_1) # book2节点添加子节点book2_1 book3.appendChild(book3_1) # book3节点添加子节点book3_1 root.appendChild(book1) # root节点添加子节点book1 root.appendChild(book2) # root节点添加子节点book2 root.appendChild(book3) # root节点添加子节点book3 # 将内容写入book.xml，设置encoding='utf-8'是为了中文不乱码 with open("book.xml", "w", encoding='utf-8') as f: doc.writexml(f, indent='\t', addindent='\t', newl='\n', encoding="utf-8") def main(): writexml() if __name__ == '__main__': main()
创建的book.xml如下
<?xml version="1.0" encoding="utf-8"?> <BOOK Description="This is a book store" Name="Happy Home"> <book Name="C++"> <book language="Chinese">C++从入门到精通</book> <book language="Chinese">C++程序设计语言</book> </book> <book Name="Python"> <book language="Chinese">Python从入门到精通</book> </book> <book Name="Linux"> <book language="Chinese">Linux从入门到精通</book> </book> </BOOK>
b. 用法介绍：
1. 创建文本对象
2. 创建根节点
3. 创建节点属性
4. 创建文本节点
5. 添加子节点
6. 写xml
二、 用xml.dom.minidom读xml
a. 读XML使用范例：
book.xml
<?xml version="1.0" encoding="utf-8"?> <BOOK Description="This is a book store" Name="Happy Home"> first node <book Name="C++"> <book language="Chinese">C++从入门到精通</book> <book language="Chinese">C++程序设计语言</book> </book> <book Name="Python"> <book language="Chinese">Python从入门到精通</book> </book> <book Name="Linux"> <book language="Chinese">Linux从入门到精通</book> </book> last node </BOOK>
book1.xml
<?xml version="1.0" encoding="utf-8"?> <BOOK Description="This is a book store" Name="Happy Home"><book Name="C++"> <book language="Chinese">C++从入门到精通</book> <book language="Chinese">C++程序设计语言</book> </book><book Name="Python"> <book language="Chinese">Python从入门到精通</book> </book><book Name="Linux"> <book language="Chinese">Linux从入门到精通</book> </book></BOOK>
readxml.py
#!/usr/bin/env python # _*_ coding: UTF-8 _*_ """================================================= @Project -> File : autocreatexml -> readxml.py @IDE : PyCharm @Author : zihan @Date : 2021/10/15 13:28 @Desc : =================================================""" import xml.dom.minidom import os def readxml(): if not os.path.exists("book.xml"): # 判断XML存不存在 return try: book_obj = xml.dom.minidom.parse("book.xml") # 判断XML格式是否正确 except: print("book.xml format wrong") return root_node = book_obj.documentElement # 获取根节点 print(root_node.nodeName) # 打印节点名称 if root_node.hasAttribute("Description"): # 判断节点是否存在属性"Description" print(root_node.getAttribute("Description")) # 打印节点属性"Description"的值 second_nodes = root_node.childNodes # 获取根节点下的子节点，但是得到的列表除了三个节点对象以外还包括了文本（其实就是XML中的空行） print(len(second_nodes)) # 结果是7，如果将book.xml中的格式换行去掉，那么结果是3 for second_node in second_nodes: print(second_node.nodeName, end="\t") # 打印节点名称[text, book, text, book, text, book, text] print("") print(root_node.firstChild) # 获取根节点下第一个子节点，如果XML的格式是节点之间有空行的话，那么第一个子节点是文本节点 print(root_node.lastChild) # 获取根节点下最后一个子节点，如果XML的格式是节点之间有空行的话，那么最后一个子节点是文本节点 book_nodes = root_node.getElementsByTagName("book") # 获取根节点下所有book节点（注意包含子节点及其下所有book节点） print(len(book_nodes)) # 结果是7，获取的root下所有的book节点 for book_node in book_nodes: print(book_node.nodeName) if book_node.hasAttribute("language"): print(book_node.childNodes[0].data, end="\t") # 打印节点value值 print(book_node.childNodes[0].nodeValue) # 打印节点value值 def main(): readxml() if __name__ == '__main__': main()
如果读的是book.xml，那么输出结果如下：
BOOK This is a book store 7 #text book #text book #text book #text <DOM Text node "'\n\t\t'"> <DOM Text node "'\n'"> 7 book book C++从入门到精通 C++从入门到精通 book C++程序设计语言 C++程序设计语言 book book Python从入门到精通 Python从入门到精通 book book Linux从入门到精通 Linux从入门到精通
如果读的是book1.xml，那么输出结果如下：
BOOK This is a book store 3 book book book <DOM Element: book at 0x4231670> <DOM Element: book at 0x4231800> 7 book book C++从入门到精通 C++从入门到精通 book C++程序设计语言 C++程序设计语言 book book Python从入门到精通 Python从入门到精通 book book Linux从入门到精通 Linux从入门到精通
b. 用法介绍：
1. 获取文本对象
2. 获取根节点
3. 获取根节点名称
4. 判断节点属性是否存在
5. 获取节点属性的值
6. 根据节点名获取其下所有节点对象。（这里是指的是所有book节点，并不单是子节点的book）
7. 获取当前节点下的子节点。需要注意xml的格式问题，如果节点之间有空行，是会被算作一个文本节点的。（book.xml中根节点下的子节点间就是有空行的，book1.xml中根节点下的子节点间就是没有空行的）
8. 获取当前节点的第一个子节点
9. 获取当前节点的最后一个子节点
10. 获取节点的value值
或者
三、用xml.etree.ElementTree写XML
a. 写xml使用范例：
writexml.py
#!/usr/bin/env python # _*_ coding: UTF-8 _*_ """================================================= @Project -> File : writexml.py @IDE : PyCharm @Author : zihan @Date : 2021/10/16 9:36 @Desc : =================================================""" from xml.etree import ElementTree as ET def writexml_way1(): root_dic = { "Description": "This is a book store", "Name": "Happy Home" } root_node = ET.Element('BOOK', root_dic) # 创建根节点 book1 = ET.SubElement(root_node, 'book', {'Name': 'C++'}) # 创建根节点下子节点 book2 = ET.SubElement(root_node, 'book', {'Name': 'Python'}) # 创建根节点下子节点 book3 = ET.SubElement(root_node, 'book', {'Name': 'Linux'}) # 创建根节点下子节点 book1_1 = ET.SubElement(book1, 'book', {'language': 'Chinese'}) # 创建book1节点下子节点 book1_1.text = "C++从入门到精通" # 设置book1_1节点的value值 book1_2 = ET.SubElement(book1, 'book', {'language': 'Chinese'}) # 创建book1节点下子节点 book1_2.text = "C++程序设计语言" # 设置book1_2节点的value值 book2_1 = ET.SubElement(book2, 'book', {'language': 'Chinese'}) # 创建book2节点下子节点 book2_1.text = "Python从入门到精通" # 设置book2_1节点的value值 book3_1 = ET.SubElement(book3, 'book', {'language': 'Chinese'}) # 创建book3节点下子节点 book3_1.text = "Linux从入门到精通" # 设置book3_1节点的value值 tree = ET.ElementTree(root_node) # 生成文档对象 # xml_declaration参数是true，生成xml中会有xml格式声明；如果参数是False，那么生成的xml中直接从根节点开始 tree.write('book3.xml', encoding="utf-8", xml_declaration=True, short_empty_elements=False) def writexml_way2(): root_dic = { "Description": "This is a book store", "Name": "Happy Home" } root_node = ET.Element("BOOK", root_dic) # 创建根节点 book1 = root_node.makeelement('book', {'Name': 'C++'}) book2 = root_node.makeelement('book', {'Name': 'Python'}) book3 = root_node.makeelement('book', {'Name': 'Linux'}) book1_1 = book1.makeelement('book', {'language': 'Chinese'}) book1_1.text = "C++从入门到精通" # 设置book1_1节点的value值 book1_2 = book1.makeelement('book', {'language': 'Chinese'}) book1_2.text = "C++程序设计语言" # 设置book1_2节点的value值 book2_1 = book2.makeelement('book', {'language': 'Chinese'}) book2_1.text = "Python从入门到精通" # 设置book2_1节点的value值 book3_1 = book3.makeelement('book', {'language': 'Chinese'}) book3_1.text = "Linux从入门到精通" # 设置book3_1节点的value值 book1.append(book1_1) book1.append(book1_2) book2.append(book2_1) book3.append(book3_1) root_node.append(book1) root_node.append(book2) root_node.append(book3) tree = ET.ElementTree(root_node) tree.write('book4.xml', encoding="utf-8", xml_declaration=True, short_empty_elements=False) def main(): writexml_way1() # writexml_way2() if __name__ == '__main__': main()
book3.xml
<?xml version='1.0' encoding='utf-8'?> <BOOK Description="This is a book store" Name="Happy Home"><book Name="C++"><book language="Chinese">C++从入门到精通</book><book language="Chinese">C++程序设计语言</book></book><book Name="Python"><book language="Chinese">Python从入门到精通</book></book><book Name="Linux"><book language="Chinese">Linux从入门到精通</book></book></BOOK>
book4.xml
<?xml version='1.0' encoding='utf-8'?> <BOOK Description="This is a book store" Name="Happy Home"><book Name="C++"><book language="Chinese">C++从入门到精通</book><book language="Chinese">C++程序设计语言</book></book><book Name="Python"><book language="Chinese">Python从入门到精通</book></book><book Name="Linux"><book language="Chinese">Linux从入门到精通</book></book></BOOK>
结果可以看出ET和minidom生成XML的格式是不同的，用ET生成的xml节点之间是不包含空行的，用minidom生成的xml格式会更加的美观，包含的空行
b. 用法介绍：
1. 创建根节点及其属性
2. 创建子节点及其属性
或者
3. 设置节点文本信息
4. 生成xml
四、用xml.etree.ElementTree读XML
a. 读xml使用范例：
book.xml
<?xml version="1.0" encoding="utf-8"?> <BOOK Description="This is a book store" Name="Happy Home"> <book Name="C++"> <book aaa="1"> <book language="Chinese">C++从入门到精通</book> <book language="Chinese">C++程序设计语言</book> </book> </book> <book Name="Python"> <book aaa="2"> <book language="Chinese">Python从入门到精通</book> </book> </book> <book Name="Linux"> <book aaa="3"> <book language="Chinese">Linux从入门到精通</book> </book> </book> </BOOK>
readxml.py
#!/usr/bin/env python # _*_ coding: UTF-8 _*_ """================================================= @Project -> File : readxml.py @IDE : PyCharm @Author : zihan @Date : 2021/10/16 9:36 @Desc : =================================================""" from xml.etree import ElementTree as ET def readxml(): tree = ET.parse('book.xml') root = tree.getroot() root_tag = root.tag # 获取root节点的标签BOOK print(root_tag) root_attrib_dic = root.attrib # 获取root节点的属性字典{'Description': 'This is a book store', 'Name': 'Happy Home'} print(root_attrib_dic) root_text = root.text # 获取root节点的值，如果是结构清晰的XML格式，则这个值可能是一个空行+tab长空格，如果是紧凑型XML，则root节点值为None print(root_text) print("遍历子节点方法：") for root_child in root: # 遍历root的子节点 print("\t", root_child.tag, root_child.attrib) # 打印root子节点标签和属性字典 for root_child_child in root_child: print("\t\t", root_child_child.tag, root_child_child.attrib) for root_child_child_child in root_child_child: print("\t\t\t", root_child_child_child.tag, root_child_child_child.attrib, root_child_child_child.text) print("遍历特定标签子节点方法：") for root_child_1 in root.findall('book'): # 遍历root的子节点并且标签名是book print("\t", root_child_1.tag, root_child_1.attrib) # 打印root下book子节点标签和属性字典 print("用相对路径遍历特定标签子节点方法：") for root_child_1 in root.findall('./book/book'): # 遍历root的book子节点下的子节点并且标签名是book print("\t", root_child_1.tag, root_child_1.attrib) # 打印root下book子节点的book子节点标签和属性字典 print("用XPath定位元素遍历所有特定标签节点方法：") for root_child_2 in root.findall('.//book/book'): # 遍历root所有的孩子和孩子的孩子等并且标签名是book print("\t", root_child_2.tag, root_child_2.attrib) # 打印root下所有book节点的节点名和属性列表 def writexml_way1(): root_dic = { "Description": "This is a book store", "Name": "Happy Home" } root_node = ET.Element('BOOK', root_dic) # 创建根节点 book1 = ET.SubElement(root_node, 'book', {'Name': 'C++'}) # 创建根节点下子节点 book2 = ET.SubElement(root_node, 'book', {'Name': 'Python'}) # 创建根节点下子节点 book3 = ET.SubElement(root_node, 'book', {'Name': 'Linux'}) # 创建根节点下子节点 book1_1 = ET.SubElement(book1, 'book', {'language': 'Chinese'}) # 创建book1节点下子节点 book1_1.text = "C++从入门到精通" # 设置book1_1节点的value值 book1_2 = ET.SubElement(book1, 'book', {'language': 'Chinese'}) # 创建book1节点下子节点 book1_2.text = "C++程序设计语言" # 设置book1_2节点的value值 book2_1 = ET.SubElement(book2, 'book', {'language': 'Chinese'}) # 创建book2节点下子节点 book2_1.text = "Python从入门到精通" # 设置book2_1节点的value值 book3_1 = ET.SubElement(book3, 'book', {'language': 'Chinese'}) # 创建book3节点下子节点 book3_1.text = "Linux从入门到精通" # 设置book3_1节点的value值 tree = ET.ElementTree(root_node) # 生成文档对象 # xml_declaration参数是true，生成xml中会有xml格式声明；如果参数是False，那么生成的xml中直接从根节点开始 tree.write('book3.xml', encoding="utf-8", xml_declaration=True, short_empty_elements=False) def writexml_way2(): root_dic = { "Description": "This is a book store", "Name": "Happy Home" } root_node = ET.Element("BOOK", root_dic) # 创建根节点 book1 = root_node.makeelement('book', {'Name': 'C++'}) book2 = root_node.makeelement('book', {'Name': 'Python'}) book3 = root_node.makeelement('book', {'Name': 'Linux'}) book1_1 = book1.makeelement('book', {'language': 'Chinese'}) book1_1.text = "C++从入门到精通" # 设置book1_1节点的value值 book1_2 = book1.makeelement('book', {'language': 'Chinese'}) book1_2.text = "C++程序设计语言" # 设置book1_2节点的value值 book2_1 = book2.makeelement('book', {'language': 'Chinese'}) book2_1.text = "Python从入门到精通" # 设置book2_1节点的value值 book3_1 = book3.makeelement('book', {'language': 'Chinese'}) book3_1.text = "Linux从入门到精通" # 设置book3_1节点的value值 book1.append(book1_1) book1.append(book1_2) book2.append(book2_1) book3.append(book3_1) root_node.append(book1) root_node.append(book2) root_node.append(book3) tree = ET.ElementTree(root_node) tree.write('book4.xml', encoding="utf-8", xml_declaration=True, short_empty_elements=False) def main(): # writexml_way1() # writexml_way2() readxml() if __name__ == '__main__': main()
输出结果：
BOOK
{'Description': 'This is a book store', 'Name': 'Happy Home'}
遍历子节点方法：
book {'Name': 'C++'}
book {'aaa': '1'}
book {'language': 'Chinese'} C++从入门到精通
book {'language': 'Chinese'} C++程序设计语言
book {'Name': 'Python'}
book {'aaa': '2'}
book {'language': 'Chinese'} Python从入门到精通
book {'Name': 'Linux'}
book {'aaa': '3'}
book {'language': 'Chinese'} Linux从入门到精通
遍历特定标签子节点方法：
book {'Name': 'C++'}
book {'Name': 'Python'}
book {'Name': 'Linux'}
用相对路径遍历特定标签子节点方法：
book {'aaa': '1'}
book {'aaa': '2'}
book {'aaa': '3'}
用XPath定位元素遍历所有特定标签节点方法：
book {'aaa': '1'}
book {'language': 'Chinese'}
book {'language': 'Chinese'}
book {'aaa': '2'}
book {'language': 'Chinese'}
book {'aaa': '3'}
book {'language': 'Chinese'}
b. 用法介绍
1. 读取文本对象
2. 获取根节点
3. 获取节点标签
4. 获取节点属性字典
5. 获取节点的值，这个地方要注意不同XML格式获取到的值不同
6. 获取子节点
7. 获取特定标签子节点
8. 获取所有特定标签的节点
未完待续。。。
