将 Python XML ElementTree 转换为字符串

Converting a Python XML ElementTree to a String

提问by user984003

I need to convert an XML ElementTreeto a String after altering it. It's the toString part that isn't working.

我需要在更改XML ElementTree后将其转换为 String。这是 toString 部分不起作用。

import xml.etree.ElementTree as ET

tree = ET.parse('my_file.xml')
root = tree.getroot()

for e in root.iter('tag_name'):
    e.text = "something else" # This works

# Now I want the the complete XML as a String with the alteration

I've tried various versions of the below line, with ET or ElementTree as various names, and importing toString, etc. etc,

我尝试了以下行的各种版本，使用 ET 或 ElementTree 作为各种名称，并导入 toString 等，等等，

s = tree.tostring(ET, encoding='utf8', method='xml')

I have seen Convert Python ElementTree to stringand some others, but I'm not sure how to apply it to my example.

我已经看到Convert Python ElementTree to string和其他一些，但我不确定如何将它应用于我的示例。

回答by Stephen Briney

This should work:-

这应该有效：-

xmlstr = ET.tostring(root, encoding='utf8', method='xml')

回答by Stevoisiak

How do I convert ElementTree.Elementto a String?

我如何转换ElementTree.Element为字符串？

For Python 3:

对于 Python 3：

xml_str = ElementTree.tostring(xml, encoding='unicode')

For Python 2:

对于 Python 2：

xml_str = ElementTree.tostring(xml, encoding='utf-8')

For compatibility with both Python 2 & 3:

为了与 Python 2 和 3 兼容：

xml_str = ElementTree.tostring(xml).decode()

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Example usage

示例用法

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
xml_str = ElementTree.tostring(xml).decode()
print(xml_str)

Output:

输出：

<Person Name="John" />

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Explanation

解释

Despite what the name implies, ElementTree.tostring()returns a bytestring by default in Python 2 & 3. This is an issue in Python 3, which uses Unicode for strings.

尽管顾名思义，ElementTree.tostring()在 Python 2 和 3 中默认返回一个字节串。这是 Python 3 中的一个问题，它使用 Unicode 来表示字符串。

In Python 2 you could use the strtype for both text and binary data. Unfortunately this confluence of two different concepts could lead to brittle code which sometimes worked for either kind of data, sometimes not. [...]

To make the distinction between text and binary data clearer and more pronounced, [Python 3] made text and binary data distinct types that cannot blindly be mixed together.

在 Python 2 中，您可以将str类型用于文本和二进制数据。不幸的是，这种两种不同概念的融合可能会导致脆弱的代码，这些代码有时适用于任何一种数据，有时则不适用。[...]

为了使文本和二进制数据之间的区别更清晰、更明显，[Python 3] 使文本和二进制数据具有不同的类型，不能盲目混合在一起。

^{Source: Porting Python 2 Code to Python 3}

^{来源：将Python 2 代码移植到 Python 3}

If we know what version of Python is being used, we can specify the encoding as unicodeor utf-8. Otherwise, if we need compatibility with both Python 2 & 3, we can use decode()to convert into the correct type.

如果我们知道正在使用的 Python 版本，我们可以将编码指定为unicodeor utf-8。否则，如果我们需要与 Python 2 和 3 兼容，我们可以使用decode()转换为正确的类型。

For reference, I've included a comparison of .tostring()results between Python 2 and Python 3.

作为参考，我已经包含了.tostring()Python 2 和 Python 3 之间的结果比较。

ElementTree.tostring(xml)
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml, encoding='unicode')
# Python 3: <Person Name="John" />
# Python 2: LookupError: unknown encoding: unicode

ElementTree.tostring(xml, encoding='utf-8')
# Python 3: b'<Person Name="John" />'
# Python 2: <Person Name="John" />

ElementTree.tostring(xml).decode()
# Python 3: <Person Name="John" />
# Python 2: <Person Name="John" />

Thanks to Martijn Petersfor pointing out that the strdatatype changed between Python 2 and 3.

感谢Martijn Peters指出strPython 2 和 3 之间的数据类型发生了变化。

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Why not use str()?

为什么不使用 str()？

In most scenarios, using str()would be the "cannonical" way to convert an object to a string. Unfortunately, using this with Elementreturns the object's location in memory as a hexstring, rather than a string representation of the object's data.

在大多数情况下， usingstr()是将对象转换为字符串的“规范”方式。不幸的是，使用 this withElement返回对象在内存中的位置作为十六进制字符串，而不是对象数据的字符串表示。

from xml.etree import ElementTree

xml = ElementTree.Element("Person", Name="John")
print(str(xml))  # <Element 'Person' at 0x00497A80>