Python lxml iterprese按属性排序大型xml文件

Question

我有一个大的XML文件，我正在尝试为每个程序对图标进行排序，我想按宽度属性中的值降序排列图标，我已经设法删除了某些不需要的图标，但我不确定如何排序图标，如有帮助，将不胜感激。

这是我用来删除一个我不想要的图标的代码，但我不确定如何订购。我使用iterparse，因为读取整个文件会占用大量内存。

当前删除代码：

import lxml.etree as ET
xml_source = 'ss_sky_sw_xmltv.xml'
xml_output = 'ss_sky_sw_xmltv_parsed.xml'
context = ET.iterparse(xml_source, encoding='iso-8859-1', tag='icon')
for event, elem in context:
if elem.getparent().tag != 'channel' :
if elem.tag == 'icon':
if elem.attrib['width'] == '180' and elem.attrib['height'] == '135':
elem.getparent().remove(elem)
elif elem.attrib['width'] == '120' and elem.attrib['height'] == '180':
elem.getparent().remove(elem)
ET.ElementTree(context.root).write(xml_output, xml_declaration=True)

XML文件：

<tv source-info-name="Schedules Direct" generator-info-name="mc2xml" generator-info-url="mailto:[e-mail]">
<channel id="I963.24337.schedulesdirect.org">
<display-name>963 BBC1SE</display-name>
<display-name>963</display-name>
<display-name>BBC1SE</display-name>
<display-name>BBC One South East</display-name>
<display-name>BBC1</display-name>
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/stationLogos/s24337_h3_aa.png" width="360" height="270" />
</channel>
<channel id="I964.24326.schedulesdirect.org">
<display-name>964 BBC1STH</display-name>
<display-name>964</display-name>
<display-name>BBC1STH</display-name>
<display-name>BBC One South</display-name>
<display-name>BBC1</display-name>
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/stationLogos/s24326_h3_aa.png" width="360" height="270" />
</channel>
<programme start="20191007150000 +0100" stop="20191007154500 +0100" channel="I101.24327.schedulesdirect.org">
<title lang="en">Escape to the Perfect Town</title>
<sub-title lang="en">Knaresborough, North Yorkshire</sub-title>
<desc lang="en">Steve Brown helps a couple feeling the pinch of the London property market to decide on their perfect town and the right property in which to raise their young children. They're amazed by what their £280,000 budget can buy them out of the capital city, and that moving to a desirable town means buzzing high streets, great community spirit and green spaces, as well as a quick commute to York for a teaching job is all on their doorstep.</desc>
<credits>
<producer>John Comerford</producer>
<producer>Eleanor Brocklehurst</producer>
</credits>
<date>20191007</date>
<category lang="en">House/garden</category>
<category lang="en">Home improvement</category>
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_v6_aa.jpg" width="120" height="180" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_v2_aa.jpg" width="135" height="180" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h5_aa.jpg" width="180" height="135" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h14_aa.jpg" width="240" height="135" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_v5_aa.jpg" width="240" height="360" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_v3_aa.jpg" width="270" height="360" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_h3_aa.jpg" width="360" height="270" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h13_aa.jpg" width="480" height="270" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_v7_aa.jpg" width="480" height="720" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_v4_aa.jpg" width="540" height="720" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h6_aa.jpg" width="720" height="540" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_h12_aa.jpg" width="960" height="540" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_h11_aa.jpg" width="1280" height="720" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_v8_aa.jpg" width="960" height="1440" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_v9_aa.jpg" width="1080" height="1440" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h9_aa.jpg" width="1440" height="1080" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p17421608_st_h10_aa.jpg" width="1920" height="1080" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p17421608_st_h2_aa.jpg" width="2048" height="1024" />
<episode-num system="dd_progid">EP03325404.0001</episode-num>
<episode-num system="xmltv_ns">0.0.</episode-num>
<new />
</programme>
<programme start="20191007154500 +0100" stop="20191007163000 +0100" channel="I101.24327.schedulesdirect.org">
<title lang="en">Make Me a Dealer</title>
<sub-title lang="en">Liverpool: Sarah &amp; Marika</sub-title>
<desc lang="en">Paul Martin teaches two antiques lovers the tricks of the trade and turns them into successful antiques dealers. In Liverpool, hairdresser Sarah faces off against civil servant Marika.</desc>
<credits>
<director>Gabe Crozier</director>
<director>Dan Donnelly</director>
<producer>Paul Tucker</producer>
<producer>Carole Lochhead</producer>
<producer>Jo Dunscombe</producer>
<presenter>Paul Martin</presenter>
</credits>
<date>20191007</date>
<category lang="en">How-to</category>
<category lang="en">Collectibles</category>
<category lang="en">Art</category>
<category lang="en">Arts/crafts</category>
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v6_aa.jpg" width="120" height="180" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_v2_aa.jpg" width="135" height="180" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_h5_aa.jpg" width="180" height="135" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_h14_aa.jpg" width="240" height="135" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v5_aa.jpg" width="240" height="360" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v3_aa.jpg" width="270" height="360" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_h3_aa.jpg" width="360" height="270" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_h13_aa.jpg" width="480" height="270" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v7_aa.jpg" width="480" height="720" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_v4_aa.jpg" width="540" height="720" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_h6_aa.jpg" width="720" height="540" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_h12_aa.jpg" width="960" height="540" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_h11_aa.jpg" width="1280" height="720" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v8_aa.jpg" width="960" height="1440" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_v9_aa.jpg" width="1080" height="1440" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_h9_aa.jpg" width="1440" height="1080" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_h10_aa.jpg" width="1920" height="1080" />
<icon src="https://s3.amazonaws.com/schedulesdirect/assets/p16172084_b_v12_aa.jpg" width="1920" height="2880" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_v13_aa.jpg" width="2160" height="2880" />
<icon src="https://json.schedulesdirect.org/20141201/image/assets/p16172084_b_s4_aa.jpg" width="3000" height="3000" />
<episode-num system="dd_progid">EP03082486.0021</episode-num>
<episode-num system="xmltv_ns">1.0.</episode-num>
<new />
</programme>
</tv>

Answer 1

import lxml.etree as ET
from copy import deepcopy
xml_source = 'ss_sky_sw_xmltv.xml'
xml_output = 'ss_sky_sw_xmltv_parsed.xml'
# icons with these dimensions (width, height) will be removed:
remove_dimensions = (
(180, 135),
(120, 180),
)
tree = ET.parse(xml_source)
root = tree.getroot()
for programme in root.iterfind('programme'):
# Create copy of all icons to reinsert them in the right order
icons = deepcopy(sorted(programme.findall('icon'), key=lambda x: int(x.attrib['height'])))
# Remove all icons from programme
for old_icon in programme.findall('icon'):
programme.remove(old_icon)
# Reinsert the items
for new_icon in icons:
# Create a dict to compare
dimensions = int(new_icon.attrib['width']), int(new_icon.attrib['height'])
# Compare the dict if it should be removed (not included again)
if dimensions not in remove_dimensions:
programme.append(new_icon)
# Save the file
tree.write(xml_output, xml_declaration=True, pretty_print=True)