如何使用Python无重复地添加XML元素
如何使用Python无重复地添加XML元素
提问于 2018-08-02 20:41:59
使用Python提取元数据XML文件，从Python脚本填充各种元素，然后将XML文件保存回其源文件。有一个已有的名为'citeinfo‘的元素，我试图在其中创建几个子元素，一个名为"pubdate“，另一个名为"othercit”。当我运行这个脚本时，我没有得到任何错误，但是当我打开XML后处理时，我得到了第二个元素组，它是"citeinfo“的父元素，并且我的所有新元素都只有一行。这是我的Python：
import arcpy, sys
from xml.etree.ElementTree import ElementTree
from xml.etree.ElementTree import Element, SubElement
import xml.etree.ElementTree as ET
from arcpy import env
env.overwriteOutput = True
fcpath = r"...\HL Metadata to BR Sample Data.gdb\NCI20102014_Oral"
translatorpath = r"...\Translator\ARCGIS2FGDC.xml"
xmlfile = r"...\Extras\FullMetaFC.xml"
arcpy.ExportMetadata_conversion(fcpath, translatorpath, xmlfile)
tree = ElementTree()
tree.parse(xmlfile)
a = tree.find('idinfo')
aa = tree.find('metainfo')
aaa = tree.find('eainfo')
b = ET.SubElement(a, 'citation')
c = ET.SubElement(b, 'citeinfo')
bb = ET.SubElement(c, 'pubdate')
d = ET.SubElement(c, 'othercit')
e = ET.SubElement(a, 'descript')
f = ET.SubElement(e, 'abstract')
g = ET.SubElement(e, 'purpose')
title = tree.find("idinfo/citation/citeinfo/title")
public_date = tree.find("idinfo/citation/citeinfo/pubdate")
cit_source = tree.find("idinfo/citation/citeinfo/othercit")
abstract = tree.find("idinfo/descript/abstract")
purpose = tree.find("idinfo/descript/purpose")
title.text = "Oral Cancer Incidence by County"
bb.text = "99990088"
d.text = "https://statecancerprofiles.cancer.gov/"
abstract.text = "Incidence rates are..."
purpose.text = "The State Cancer Profiles..."
tree.write(xmlfile)
arcpy.ImportMetadata_conversion(xmlfile, "FROM_FGDC", fcpath, "ENABLED")下面是XML：
<citation>
<citeinfo>
<origin>X</origin>
<title>META_TESTING</title>
<geoform>vector digital data</geoform>
<pubdate>20102010</pubdate><othercit>www.google.com</othercit></citeinfo>
</citation>我希望“引用”组看起来像这样：
<citation>
<citeinfo>
<title>National Cancer Institute, Oral Cancer Incidence by County</title>
<geoform>vector digital data</geoform>
<pubdate>20120510</pubdate>
<othercit>www.google.com</othercit>
</citeinfo>
</citation>回答 1
Stack Overflow用户
发布于 2018-08-02 22:41:57
我会创建一个小助手函数来确保元素的存在。如果它存在，它会返回它-如果不存在，它就会创建它。
def ensure_elem(context, name):
elem = context.find(name)
return ET.SubElement(context, name) if elem is None else elem现在您可以执行以下操作：
tree = ET.parse(xmlfile)
# ensure we have a /metadata/idinfo/citation/citeinfo hierarchy
metadata = tree.getroot()
idinfo = ensure_elem(metadata, "idinfo")
citation = ensure_elem(idinfo, "citation")
citeinfo = ensure_elem(citation, "citeinfo")
# update the text of elements beneath citeinfo
ensure_elem(citeinfo, 'pubdate').text = "new pubdate"
ensure_elem(citeinfo, 'title').text = "new title"
# ...and so on
tree.write(xmlfile)请注意，您可以在一行代码中ET.parse()一个文件。
为了简单起见，我们可以这样做：
e = ensure_elem
# ensure we have a /metadata/idinfo/citation/citeinfo hierarchy
citeinfo = e(e(e(tree.getroot(), "idinfo"), "citation"), "citeinfo")要美观地打印ElementTree文档，可以使用以下函数：
def indent(tree, indent_by=' '):
irrelevant = lambda s: s is None or s.lstrip('\r\n\t\v ') == ''
indent_str = lambda i: '\n' + indent_by * i
def indent(elem, level=0, last_child=True):
if len(elem) and irrelevant(elem.text):
elem.text = indent_str(level+1)
if irrelevant(elem.tail):
elem.tail = indent_str(level-(1 if last_child else 0))
for i, child in enumerate(elem, 1):
indent(child, level+1, i==len(elem))
indent(tree.getroot())页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/51653954
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