python基础-xml模块

Posted 2020-12-21 枫叶学python

xml 是实现不通语言或程序之间进行数据交换的协议，可扩展标记语言，标准通用标记语言的子集。是一种用于标记电子文件使其具有结构性的标记语言。xml格式如下，是通过<>节点来区别数据结构的。xml在各种语言都是支持的。

如下

<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year updated="yes">2010</year>
        <gdppc>141100</gdppc>
        <neighbor direction="E" name="Austria" />
        <neighbor direction="W" name="Switzerland" />
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year updated="yes">2013</year>
        <gdppc>59900</gdppc>
        <neighbor direction="N" name="Malaysia" />
    </country>
</data>

1.xml文件读取

a.节点

import xml.etree.ElementTree as ET

tree = ET.parse(\'test.xml\')  # parse 解析一个xml文件
root = tree.getroot()  # 根节点
print(root)
print(root.tag)
for i in root:
    print(i.tag)  # 子节点
    for j in i:  # 孙节点
        print(j.tag)

 

 b.attrib属性，text文本

import xml.etree.ElementTree as ET

tree = ET.parse(\'test.xml\')  # parse 解析一个xml文件
root = tree.getroot()  # 根节点
for i in root:
    for j in i:
        print(j.attrib)  #属性
        print(j.text) #文本

 

c.def iter(self, tag=None):-迭代器：

源码解释的是Create tree iterator.

The iterator loops over the element and all subelements in document
order, returning all elements with a matching tag.
就是迭代所有节点，找出tag对应的节点

import xml.etree.ElementTree as ET

tree = ET.parse(\'test.xml\')
root = tree.getroot()
for i in root.iter("year"):  # iter为所有节点,不传参为所有节点。传参寻找tag的节点
    print(i.tag, i.attrib, i.text)

2.xml修改

import xml.etree.ElementTree as ET

tree = ET.parse(\'test.xml\')
root = tree.getroot()
for i in root.iter("year"):  # iter为所有节点
    print(type(i.text))  # text为str格式
    \'\'\'修改\'\'\'
    new_year = int(i.text) + 1  #
    i.text = str(new_year)
    i.set(\'updated\', \'yes\')  # 原文提示是Set element attribute 设置属性
    \'\'\'tree已经修改，还需要写入xml文件\'\'\'
tree.write(\'test_new.xml\')

3.xml删除

import xml.etree.ElementTree as ET

tree = ET.parse(\'test.xml\')
root = tree.getroot()
for i in root.findall(\'country\'):#"""Find all matching subelements by tag name or path.
    rank=i.find(\'rank\').text
    rank=int(rank)
    if rank>1:
        root.remove(i) #只是tree修改了，还需要写入xml
tree.write(\'test.xml\')

4.用python写xml

import xml.etree.ElementTree as ET

new_xml=ET.Element(\'namelist\') #根节点
name=ET.SubElement(new_xml,\'name\',attrib={\'enrolled\':\'yes\'}) #def SubElement(parent, tag, attrib={}, **extra):
age=ET.SubElement(name,\'age\',attrib={\'check\':\'yes\'})
sex=ET.SubElement(name,\'one\')
name1=ET.SubElement(new_xml,\'name\',attrib={\'enrolled\':\'no\'}) #def SubElement(parent, tag, attrib={}, **extra):
age=ET.SubElement(name1,\'age\',attrib={\'check\':\'no\'})
age.text=\'19\'
sex=ET.SubElement(name1,\'two\')

et=ET.ElementTree(new_xml)#生成文档对象
et.write(\'test.xml\')