Question

我有一个现有的xml文件如下：

<vehicleTravelTimeMeasurements>
        <vehicleTravelTimeMeasurement name="ckkkkkkkkkk" no="2">
            <start link="1" pos="3.864983"/>
            <end link="3" pos="23.275375"/>
        </vehicleTravelTimeMeasurement>
        <vehicleTravelTimeMeasurement name="" no="3">
            <start link="1" pos="3.864983"/>
            <end link="2" pos="13.275375"/>
        </vehicleTravelTimeMeasurement>
</vehicleTravelTimeMeasurements>

我正在尝试使用xml.etree.cElementTree构建如上所示的相同格式，并将它们正确地添加到xml中：

new = ET.Element("vehicleTravelTimeMeasurement", name = "kkk", no = "4")
newsub1 =  ET.Element("start", link = "1", pos="3.88888")
newsub2 = ET.Element("end",link = "3", pos = "3.88888")

有人可以帮我解决这个问题吗？

提前谢谢！

Answer 1

您想使用SubElement并将start和end元素添加到vehicleTravelTimeMeasurement元素。然后在位置2插入新创建的元素，因为0和1已被占用。

import xml.etree.ElementTree as ET

def indent(elem, level=0):
    i = "\n" + level*"  "
    if len(elem):
        if not elem.text or not elem.text.strip():
            elem.text = i + "  "
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
        for elem in elem:
            indent(elem, level+1)
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
    else:
        if level and (not elem.tail or not elem.tail.strip()):
            elem.tail = i

xml = '''<vehicleTravelTimeMeasurements>
        <vehicleTravelTimeMeasurement name="ckkkkkkkkkk" no="2">
            <start link="1" pos="3.864983"/>
            <end link="3" pos="23.275375"/>
        </vehicleTravelTimeMeasurement>
        <vehicleTravelTimeMeasurement name="" no="3">
            <start link="1" pos="3.864983"/>
            <end link="2" pos="13.275375"/>
        </vehicleTravelTimeMeasurement>
</vehicleTravelTimeMeasurements>'''

root = ET.fromstring(xml)
new = ET.Element("vehicleTravelTimeMeasurement", name = "kkk", no = "4")
newsub1 = ET.SubElement(new, "start", link = "1", pos="3.88888")
newsub2 = ET.SubElement(new, "end",link = "3", pos = "3.88888")
root.insert(2, new)
indent(root)
with open('test.xml', 'w') as f:
    f.write(ET.tostring(root))

Answer 2

短版/ 更新＆amp;编辑：

您唯一需要做的就是（A）将newsub1和newsub2添加到new。并且（B）将new添加到root。

root = ET.fromstring(xml) # or whichever way you're getting `root` # these 3 lines form your code: new = ET.Element('vehicleTravelTimeMeasurement', name="kkk", no="4") newsub1 = ET.Element('start', link='1', pos='3.88888') newsub2 = ET.Element('end', link='3', pos='3.88888') # the next steps to add new.append(newsub1) new.append(newsub2) root.append(new)

注意（A）＆amp; （B）可以按任何顺序完成，这可以缩短，如下所示：

>>> root = ET.fromstring(xml) >>> new = ET.Element('vehicleTravelTimeMeasurement', name="kkk", no="4") >>> root.append(new) # note that I've immediately added `new` >>> ET.SubElement(new, 'start', link='1', pos='3.88888') <Element 'start' at 0x24707b8> >>> ET.SubElement(new, 'end', link='3', pos='3.88888') <Element 'end' at 0x24ea978> >>> # there's no need to store the subelements in `newsub1` and ... # `newsub2` if you don't need to do anything with them ... >>> indent(root) >>> print ET.tostring(root) <vehicleTravelTimeMeasurements> <vehicleTravelTimeMeasurement name="ckkkkkkkkkk" no="2"> <start link="1" pos="3.864983" /> <end link="3" pos="23.275375" /> </vehicleTravelTimeMeasurement> <vehicleTravelTimeMeasurement name="" no="3"> <start link="1" pos="3.864983" /> <end link="2" pos="13.275375" /> </vehicleTravelTimeMeasurement> <vehicleTravelTimeMeasurement name="kkk" no="4"> <start link="1" pos="3.88888" /> <end link="3" pos="3.88888" /> </vehicleTravelTimeMeasurement> </vehicleTravelTimeMeasurements>

注意：

我在创建它之后就已将new添加到root。

如果您知道自己一直在追加，请使用append代替insert，而不是需要跟踪原始xml中的no

除非您无论如何都需要阅读以计算下一个“no”属性

ET.SubElement(new)更新new（以及root），即使new已被附加。

如果您不需要对子元素执行任何操作，则无需将子元素存储在newsub1和newsub2中。

第一种方法（与您的一样）创建元素，然后将它们添加到root或new。

第二种方法使用ET.SubElement(new, ...)将元素添加到其父级。

function indent is from here，quotes this source。

上面的Re＃4.2，也可以这样做：

root = ET.fromstring(xml) new = ET.SubElement(root, 'vehicleTravelTimeMeasurement', name="kkk", no="4") # `new` is already created as a subelement of `root` and appended ET.SubElement(new, 'start', link='1', pos='3.88888') ET.SubElement(new, 'end', link='3', pos='3.88888')

来自Subelement docs：

此函数创建一个元素实例，将附加到现有元素。

（强调我的）

在现有的xml文件python中添加元素

2 个答案: