1

几天来，我一直在尝试解析 xml 文件中的数据，但无法正常工作。从下面的示例中，我需要每个图层的状态、索引以及前景/生产者类型和文件名。问题是结构因内容而异。查看索引 2，其中文件名位于foreground/producer/fill/producer 下（我不需要foreground/producer/key/producer 下的文件名）。我正在寻找一个简单的解决方案（一直在尝试使用 etree.ElementTree 但解析似乎很困难）。

<?xml version="1.0" encoding="utf-8"?>
<channel>
   <video-mode>1080i5000</video-mode>
   <stage>
      <layers>
         <layer>
            <status>stopped</status>
            <auto_delta>-1</auto_delta>
            <frame-number>1829997</frame-number>
            <nb_frames>0</nb_frames>
            <frames-left>-1829996</frames-left>
            <foreground>
               <producer>
                  <type>empty-producer</type>
               </producer>
            </foreground>
            <background>
               <producer>
                  <type>transition-producer</type>
                  <source>
                     <producer>
                        <type>empty-producer</type>
                     </producer>
                  </source>
                  <destination>
                     <producer>
                        <type>ffmpeg-producer</type>
                        <filename>media\\MULTI\testfile2.mpg</filename>
                        <width>1920</width>
                        <height>1080</height>
                        <progressive>true</progressive>
                        <fps>25</fps>
                        <loop>false</loop>
                        <frame-number>0</frame-number>
                        <nb-frames>4396</nb-frames>
                        <file-frame-number>0</file-frame-number>
                        <file-nb-frames>4396</file-nb-frames>
                     </producer>
                  </destination>
               </producer>
            </background>
            <index>0</index>
         </layer>
         <layer>
            <status>playing</status>
            <auto_delta>-1</auto_delta>
            <frame-number>1830920</frame-number>
            <nb_frames>4294967295</nb_frames>
            <frames-left>4293136376</frames-left>
            <foreground>
               <producer>
                  <type>ffmpeg-producer</type>
                  <filename>media\AMB.mp4</filename>
                  <width>720</width>
                  <height>576</height>
                  <progressive>true</progressive>
                  <fps>25</fps>
                  <loop>true</loop>
                  <frame-number>1830920</frame-number>
                  <nb-frames>4294967295</nb-frames>
                  <file-frame-number>520</file-frame-number>
                  <file-nb-frames>1600</file-nb-frames>
               </producer>
            </foreground>
            <background>
               <producer>
                  <type>empty-producer</type>
               </producer>
            </background>
            <index>1</index>
         </layer>
         <layer>
            <status>playing</status>
            <auto_delta>-1</auto_delta>
            <frame-number>1830758</frame-number>
            <nb_frames>4294967295</nb_frames>
            <frames-left>4293136538</frames-left>
            <foreground>
               <producer>
                  <type>separated-producer</type>
                  <fill>
                     <producer>
                        <type>ffmpeg-producer</type>
                        <filename>media\action.mpg</filename>
                        <width>1920</width>
                        <height>1080</height>
                        <progressive>false</progressive>
                        <fps>25</fps>
                        <loop>true</loop>
                        <frame-number>1830758</frame-number>
                        <nb-frames>4294967295</nb-frames>
                        <file-frame-number>22</file-frame-number>
                        <file-nb-frames>247</file-nb-frames>
                     </producer>
                  </fill>
                  <key>
                     <producer>
                        <type>ffmpeg-producer</type>
                        <filename>media\action_a.mpg</filename>
                        <width>1920</width>
                        <height>1080</height>
                        <progressive>false</progressive>
                        <fps>25</fps>
                        <loop>true</loop>
                        <frame-number>1830758</frame-number>
                        <nb-frames>4294967295</nb-frames>
                        <file-frame-number>22</file-frame-number>
                        <file-nb-frames>247</file-nb-frames>
                     </producer>
                  </key>
               </producer>
            </foreground>
            <background>
               <producer>
                  <type>empty-producer</type>
               </producer>
            </background>
            <index>2</index>
         </layer>
      </layers>
   </stage>
   <mixer/>
   <output>
      <consumers>
         <consumer>
            <type>oal-consumer</type>
            <index>500</index>
         </consumer>
         <consumer>
            <type>ogl-consumer</type>
            <key-only>false</key-only>
            <windowed>true</windowed>
            <auto-deinterlace>true</auto-deinterlace>
            <index>600</index>
         </consumer>
      </consumers>
   </output>
   <index>0</index>
</channel>
4

2 回答 2

0 
import xml.etree.ElementTree as ET                                              
tree = ET.parse('x.xml')                                                        
root = tree.getroot()                                                           

for child in root:                                                              
    print child.tag                                                             
    for child2 in child:                                                        
        print '> ',child2.tag                                                   

'''                                                                             
====                                                                            
output                                                                          
====                                                                            
video-mode                                                                      
stage                                                                           
>  layers                                                                       
mixer                                                                           
output                                                                          
>  consumers                                                                    
index                                                                           

'''

关于问题：“结构因内容而异。” 每个 XML 都是根据一个定义，即 DTD 来定义的。文件的结构不能在内部更改，否则将是不明确的。如果你的意思是，你想根据节点上方的叶子解析树的部分，你将不得不想出一些 if then else 语句和函数，例如：

import xml.etree.ElementTree as ET                                              
tree = ET.parse('x.xml')                                                        
root = tree.getroot()                                                           

def parseStageTag(element):                                                     
    print 'parsing Stage'                                                       
    for child in element:                                                       
        if child.tag=='layers':                                                 
            parseLayersTag(child)                                               

def parseOutputTag(element):                                                    
    pass                                                                        

def parseLayersTag(element):                                                    
    print 'parsing Layers'                                                      
    for child in element:                                                       
        print child                                                             


for child in root:                                                              
    if child.tag=='stage':                                                      
        parseStageTag(child)                                                    

    for child2 in child:                                                        
        print '> ',child2.tag  
'''
output
parsing Stage
parsing Layers
<Element 'layer' at 0x1079e4250>
<Element 'layer' at 0x1079e4f10>
<Element 'layer' at 0x1079e6510>
>  layers
>  consumers
'''
于 2012-11-14T10:07:41.540 回答
0

我在解析 XML 文件时发现了类似的问题，直到我发现ElementTree 对 XPath 的支持

例如，下面的代码：

import os
import xml.etree.ElementTree

os.chdir('C:/temp/blah')

et = xml.etree.ElementTree.parse('file.xml')
layerTagList = et.findall("./stage/layers/layer")

for curLayerTag in layerTagList:
    indexTag = curLayerTag.find("./index")
    print "Layer[%s]" %(indexTag.text)
    fgFiles = curLayerTag.findall(".//foreground//filename")
    for fileTag in fgFiles:
            print "  FG - %s" %(fileTag.text)
    bgFiles = curLayerTag.findall(".//background//filename")
    for fileTag in bgFiles:
            print "  BG - %s" %(fileTag.text)

给出输出：

Layer[0]
  BG - media\\MULTI\testfile2.mpg
Layer[1]
  FG - media\AMB.mp4
Layer[2]
  FG - media\action.mpg
  FG - media\action_a.mpg
于 2014-07-17T05:53:29.317 回答