xml介绍
它是一种简洁的数据存储格式，本文针对xml的解析进行了相关总结。python基于xml的解析主要有三种方法，包含SAX、DOM和ElementTree，本文就后两种方法进行讲解。
xml解析
ElementTree方法
以下列xml文件为例
<annotation>
<folder>Non_Motor_Data</folder>
<filename>PD_traffic_xuhui-image_00002-436.jpg</filename>
<size>
<width>1920</width>
<height>1080</height>
<depth>3</depth>
</size>
<object>
<name>person</name>
<pose>Unspecified</pose>
<truncated>0</truncated>
<difficult>0</difficult>
<bndbox>
<xmin>499</xmin>
<ymin>121</ymin>
<xmax>582</xmax>
<ymax>287</ymax>
</bndbox>
</object>
<object>
<name>person</name>
<pose>Unspecified</pose>
<truncated>0</truncated>
<difficult>0</difficult>
<bndbox>
<xmin>1193</xmin>
<ymin>276</ymin>
<xmax>1290</xmax>
<ymax>508</ymax>
</bndbox>
</object>
<object>
<name>person</name>
<pose>Unspecified</pose>
<truncated>0</truncated>
<difficult>0</difficult>
<bndbox>
<xmin>59</xmin>
<ymin>23</ymin>
<xmax>108</xmax>
<ymax>139</ymax>
</bndbox>
</object>
</annotation>
首先需要引入包
from xml.etree.ElementTree import ElementTree, Element
具体的我们可以通过该函数进行解析
def read_xml(xml_path):
tree=ElementTree()#建立一个有效树
tree.parse(xml_path)#解析xml文件
return tree
在获取xml解析树之后我们可以采用层级遍历该树形结构
def read_tree(tree):
root=tree.getroot()#获取tree的根节点
for child in root：
if(child.tag=='size'):
for subchild in child:
if(subchild.tag=='width'):
width=subchild.text
if(subchild.tag=='height'):
height=subchild.text
通过以上方法可以层级对xml文件进行遍历
DOM方法解析
以下面xml文件为例
<collection shelf="New Arrivals">
<movie title="Enemy Behind">
<type>War, Thriller</type>
<format>DVD</format>
<year>2003</year>
<rating>PG</rating>
<stars>10</stars>
<description>Talk about a US-Japan war</description>
</movie>
<movie title="Transformers">
<type>Anime, Science Fiction</type>
<format>DVD</format>
<year>1989</year>
<rating>R</rating>
<stars>8</stars>
<description>A schientific fiction</description>
</movie>
<movie title="Trigun">
<type>Anime, Action</type>
<format>DVD</format>
<episodes>4</episodes>
<rating>PG</rating>
<stars>10</stars>
<description>Vash the Stampede!</description>
</movie>
</collection>
首先也需要引入包
from xml.dom.minidom import parse
import xml.dom.minidom
进行xml解析
DOMTree=xml.dom.minidom.parse(xml_path)
collection=DOMTree.documentElement#获取文档集合
if collection.hasAttribute("shelf"):
print ("Root element : %s" % collection.getAttribute("shelf"))
movies = collection.getElementsByTagName("movie")
for movie in movies:
print ("*****Movie*****")
if movie.hasAttribute("title"):
print ("Title: %s" % movie.getAttribute("title"))
type = movie.getElementsByTagName('type')[0]
print ("Type: %s" % type.childNodes[0].data)
format = movie.getElementsByTagName('format')[0]
print ("Format: %s" % format.childNodes[0].data)
rating = movie.getElementsByTagName('rating')[0]
print ("Rating: %s" % rating.childNodes[0].data)
description = movie.getElementsByTagName('description')[0]
print ("Description: %s" % description.childNodes[0].data)
输出
Root element : New Arrivals
*****Movie*****
Title: Enemy Behind
Type: War, Thriller
Format: DVD
Rating: PG
Description: Talk about a US-Japan war
*****Movie*****
Title: Transformers
Type: Anime, Science Fiction
Format: DVD
Rating: R
Description: A schientific fiction
生成xml文件
首先引入包
from lxml.etree import Element, SubElement, tostring
#from xml.dom.minidom import parseString 这个可有可无
建立xml其实也很简单，也就是层级进行构建，以下语句是建立xml文件的关键点
node_root=Element('annotation')#建立根节点(建立一个节点)
node_floder = ```SubElement(node_root,'floder')```#根节点下创立子节点floder
node_floder.text = 'Non_Motor_Data'# 赋予子节点值为Non_Motor_Data
