python中lxml的应用
首先下载lxml， http://www.lfd.uci.edu/~gohlke/pythonlibs/ ，
然后添加引用
from lxml import _elementpath as DONTUSE
from lxml import etree
具体示例：
1.添加命名空间
#set namespace
nsmap = {
"xsi"
:
"http://www.w3.org/2001/XMLSchema-instance"
}
g_statisticsRoot = etree.Element(
"DcmStatistics"
, nsmap = nsmap)
2.添加xml schema引用
#add xsd reference
g_statisticsRoot.set(
"{http://www.w3.org/2001/XMLSchema-instance}noNamespaceSchemaLocation"
,
"DcmStatistics.xsd"
)
3.添加注释
#add comment， 利用addprevious添加到根节点的前面
comment = etree.Comment(
"create by jiangong.li"
)
g_statisticsRoot.addprevious(comment)
4.尝试多种编码来解析xml
def decodingXml(xmlFile):
tree = None
encoding = "utf-8"
while(True):
try:
parser = etree.XMLParser(remove_blank_text= True, encoding=encoding, remove_comments = False)
tree = etree.parse(xmlFile, parser)
except Exception as e:
if (encoding != "gb18030"):
encoding = "gb18030"
continue
else:
print( "\nPAR XML ERROR, decoding error." )
break
break
return tree
5.遍历xml下的所有子节点，不止直属第一级子节点. iter()
for element in root.iter():
element.tail = None
6.遍历xml下的第一级子节点. iterchildren()
for
e
in
srcParentNode.iterchildren():
if
e
is
srcParentNode:
continue
name =
""
#statistics node
if
e.tag ==
"element"
:
name =
"Element"
elif
e.tag ==
"sequence"
:
name =
"Sequence"
elif
e.tag ==
"item"
:
name =
"Item"
else
:
print(
"\nUnsupported element type: %s\n"
%(e.tag))
name = e.tag
# Only parse element/sequence/item
continue
7.添加子节点到尾部. append()
def getXmlElement(nodeName, parentNode):
if parentNode == None:
raise Exception( "parent node is None")
nodes = parentNode.xpath( './'+nodeName)
if len(nodes) == 0:
node = etree.Element(nodeName)
parentNode.append(node)
return node
else:
return nodes[0]
8.格式化成str输出
etree.tostring(g_statisticsRoot, encoding= "UTF-8", xml_declaration=True , pretty_print=True, with_comments=True )
9.保存成xml文件
statisticsResult = open(g_xmlName, "bw+")
statisticsResult.write(etree.tostring(g_statisticsRoot, encoding= "UTF-8", xml_declaration=True, pretty_print=True , with_comments=True))
statisticsResult.flush()
statisticsResult.close()