python - LXML + python : How to change every instance of an element

Question

我如何使用 LXML 和 Python 更改下面 Weather_ID 的每个元素？

如您所见，我基本上尝试将每个 Weather_Id 设置为新值，在本例中该值为 5。

我的现实世界示例可能有数十到数百个 Weather_Id。

<?xml version='1.0' encoding='UTF-8' standalone='yes'?>
<ProjectDataSet>
<Fx>
    <Id>1</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>2</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
    <Fx>3<Id>3</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>4</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
</ProjectDataSet>

到目前为止我已经尝试过:

from lxml import etree

text = """\
<ProjectDataSet>
<Fx>
    <Id>1</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>2</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
    <Fx>3<Id>3</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>4</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
</ProjectDataSet>
"""

root= etree.fromstring(text)


newWeatherId = 5

targets = root.xpath("//Fx[./Weather_Id]")
print(targets)
for target in targets:
    target.text = str(newWeatherId)

我要么似乎没有修改列表，没有修改 Weather_Id 标记的值，要么因为没有正确处理文本而生成各种错误。

Answer 1

你已经很接近了，你只需要正确设置你的 xpath 即可。另外为什么不打印root？

from lxml import etree

text = """
<ProjectDataSet>
<Fx>
    <Id>1</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>2</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    3
    <Id>3</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
<Fx>
    <Id>4</Id>
    <Weather_Id>2</Weather_Id>
    <Other></Other>
</Fx>
</ProjectDataSet>
"""

root= etree.fromstring(text)
newWeatherId = 5
targets = root.xpath("//Fx/Weather_Id")

for target in targets:
    target.text = str(newWeatherId)

print(etree.tostring(root))