Python_使用ElementTree解析xml文件

一般使用ElementTree之前，我都会执行：

from xml.etree import ElementTree as ET

下面是个例子：

try:    tree = ET.parse("Campaign_Config.xml") #打开xml文档    root = tree.getroot() #获得root节点except Exception, e:    print "Error: cannot parse file: Campaign_Config.xml."    return -1   eles_Paramter = root.find("Parameters").findall("Parameter") #找到Parameters节点下的所有Parameter节点for eachEle in eles_Paramter:    if eachEle.attrib.has_key("isControlled"): #如果有个节点拥有属性isControlledPSUsed        eachEle.set("isControlled", "False")    #就将该属性设置为Falsetree.write("Campaign_Config.xml")   #最后将结果写回文件

Element具有的属性和方法：

tag

A string identifying what kind of data this element represents (the element type, in other words).

text

The text attribute can be used to hold additional data associated with the element. As the name implies this attribute is usually a string but may be any application-specific object. If the element is created from an XML file the attribute will contain any text found between the element tags.

tail

The tail attribute can be used to hold additional data associated with the element. This attribute is usually a string but may be any application-specific object. If the element is created from an XML file the attribute will contain any text found after the element’s end tag and before the next tag.

attrib

A dictionary containing the element’s attributes. Note that while the attrib value is always a real mutable Python dictionary, an ElementTree implementation may choose to use another internal representation, and create the dictionary only if someone asks for it. To take advantage of such implementations, use the dictionary methods below whenever possible.

The following dictionary-like methods work on the element attributes.

clear()

Resets an element. This function removes all subelements, clears all attributes, and sets the text and tail attributes to None.

get(key,default=None)

Gets the element attribute named key.

Returns the attribute value, or default if the attribute was not found.

items()

Returns the element attributes as a sequence of (name, value) pairs. The attributes are returned in an arbitrary order.

keys()

Returns the elements attribute names as a list. The names are returned in an arbitrary order.

set(key,value)

Set the attribute key on the element to value.

The following methods work on the element’s children (subelements).

append(subelement)

Adds the element subelement to the end of this elements internal list of subelements.

extend(subelements)

Appends subelements from a sequence object with zero or more elements. RaisesAssertionError if a subelement is not a valid object.

New in version 2.7.

find(match)

Finds the first subelement matching match. match may be a tag name or path. Returns an element instance orNone.

findall(match)

Finds all matching subelements, by tag name or path. Returns a list containing all matching elements in document order.

findtext(match,default=None)

Finds text for the first subelement matching match. match may be a tag name or path. Returns the text content of the first matching element, ordefault if no element was found. Note that if the matching element has no text content an empty string is returned.

getchildren()

Deprecated since version 2.7:Uselist(elem) or iteration.

getiterator(tag=None)

Deprecated since version 2.7:Use methodElement.iter() instead.

insert(index,element)

Inserts a subelement at the given position in this element.

iter(tag=None)

Creates a tree iterator with the current element as the root. The iterator iterates over this element and all elements below it, in document (depth first) order. If tag is not None or '*', only elements whose tag equals tag are returned from the iterator. If the tree structure is modified during iteration, the result is undefined.

iterfind(match)

Finds all matching subelements, by tag name or path. Returns an iterable yielding all matching elements in document order.

New in version 2.7.

itertext()

Creates a text iterator. The iterator loops over this element and all subelements, in document order, and returns all inner text.

New in version 2.7.

makeelement(tag,attrib)

Creates a new element object of the same type as this element. Do not call this method, use theSubElement() factory function instead.

remove(subelement)

Removes subelement from the element. Unlike the find* methods this method compares elements based on the instance identity, not on tag value or contents.

ElementTree具有的属性和方法：

_setroot(element)

Replaces the root element for this tree. This discards the current contents of the tree, and replaces it with the given element. Use with care.element is an element instance.

find(match)

Finds the first toplevel element matching match. match may be a tag name or path. Same as getroot().find(match). Returns the first matching element, orNone if no element was found.

findall(match)

Finds all matching subelements, by tag name or path. Same as getroot().findall(match).match may be a tag name or path. Returns a list containing all matching elements, in document order.

findtext(match,default=None)

Finds the element text for the first toplevel element with given tag. Same as getroot().findtext(match).match may be a tag name or path.default is the value to return if the element was not found. Returns the text content of the first matching element, or the default value no element was found. Note that if the element is found, but has no text content, this method returns an empty string.

getiterator(tag=None)

Deprecated since version 2.7:Use methodElementTree.iter() instead.

getroot()

Returns the root element for this tree.

iter(tag=None)

Creates and returns a tree iterator for the root element. The iterator loops over all elements in this tree, in section order.tag is the tag to look for (default is to return all elements)

iterfind(match)

Finds all matching subelements, by tag name or path. Same as getroot().iterfind(match). Returns an iterable yielding all matching elements in document order.

New in version 2.7.

parse(source,parser=None)

Loads an external XML section into this element tree. source is a file name or file object.parser is an optional parser instance. If not given, the standard XMLParser parser is used. Returns the section root element.

write(file,encoding="us-ascii",xml_declaration=None,method="xml")

Writes the element tree to a file, as XML. file is a file name, or a file object opened for writing.encoding[1] is the output encoding (default is US-ASCII).xml_declaration controls if an XML declaration should be added to the file. Use False for never, True for always, None for only if not US-ASCII or UTF-8 (default is None).method is either"xml","html" or"text" (default is"xml"). Returns an encoded string.