防止lxml创建自动关闭标签

Question

我有一个（旧的）工具，该工具不了解像这样的自动关闭标签<STATUS/>。所以，我们需要序列与这样的开启/关闭的标签我们的XML文件：<STATUS></STATUS>。

目前我有：

>>> from lxml import etree

>>> para = """<ERROR>The status is <STATUS></STATUS>.</ERROR>"""
>>> tree = etree.XML(para)
>>> etree.tostring(tree)
'<ERROR>The status is <STATUS/>.</ERROR>'

如何使用打开/关闭的标签进行序列化？

<ERROR>The status is <STATUS></STATUS>.</ERROR>

解

由wildwilhelm给出，如下：

>>> from lxml import etree

>>> para = """<ERROR>The status is <STATUS></STATUS>.</ERROR>"""
>>> tree = etree.XML(para)
>>> for status_elem in tree.xpath("//STATUS[string() = '']"):
...     status_elem.text = ""
>>> etree.tostring(tree)
'<ERROR>The status is <STATUS></STATUS>.</ERROR>'

Answer 1

似乎<STATUS>标签已分配了的text属性None：

>>> tree[0]
<Element STATUS at 0x11708d4d0>
>>> tree[0].text
>>> tree[0].text is None
True

如果text将<STATUS>标记的属性设置为空字符串，则应获得所需的内容：

>>> tree[0].text = ''
>>> etree.tostring(tree)
'<ERROR>The status is <STATUS></STATUS>.</ERROR>'

考虑到这一点，您可能可以text在编写XML之前遍历DOM树并修复属性。像这样：

# prevent creation of self-closing tags
for node in tree.iter():
    if node.text is None:
        node.text = ''