python xml 删除孙子或曾孙

Question

我一直在谷歌搜索从 xml 文件中删除孙子。但是，我还没有找到完美的解决方案。 这是我的案例：

<tree>
    <category title="Item 1">item 1 text
        <subitem title="subitem1">subitem1 text</subitem>
        <subitem title="subitem2">subitem2 text</subitem>
    </category>

    <category title="Item 2">item 2 text
        <subitem title="subitem21">subitem21 text</subitem>
        <subitem title="subitem22">subitem22 text</subitem>
            <subsubitem title="subsubitem211">subsubitem211 text</subsubitem>
    </category>
</tree>

在某些情况下，我想删除

subitem

。在其他情况下，我想删除

subsubitem

。我知道我可以在当前给定的内容中这样做：

import xml.etree.ElementTree as ET

root = ET.fromstring(given_content)
# case 1
for item in root.getiterator():
    for subitem in item:
        item.remove(subitem)

# case 2
for item in root.getiterator():
    for subitem in item:
        for subsubitem in subitem:
            subitem.remove(subsubitem)

只有当我知道目标节点的深度时，我才能用这种风格编写。如果我只知道要删除的节点的标签名称，我应该如何实现？ 伪代码：

import xml.etree.ElementTree as ET

for item in root.getiterator():
    if item.tag == 'subsubitem' or item.tag == 'subitem':
        # remove item

如果我这样做

root.remove(item)

，它肯定会返回错误，因为 item 不是

root

的直接子项。编辑： 我无法安装任何 3rd-party-lib，所以我必须用

xml

来解决这个问题。

Answer 1

xml

lib 上完成了这项工作。

def recursive_xml(root):
    if root.getchildren() is not None:
        for child in root.getchildren():
            if child.tag == 'subitem' or child.tag == 'subsubitem':
                root.remove(child)
            else:
                recursive_xml(child)

通过这样做，该函数将迭代 ET 中的每个节点并删除我的目标节点。

test_xml = r'''
<test>
    <test1>
        <test2>
            <test3>
            </test3>
            <subsubitem>
            </subsubitem>
        </test2>
        <subitem>
        </subitem>
        <nothing_matters>
        </nothing_matters>
    </test1>
</test>
'''
root = ET.fromstring(test_xml)
recursive_xml(root)

希望这可以帮助像我这样有限制要求的人....

Answer 2

subsubitem

或

subitem

的实例，无论其深度如何，请考虑以下示例（需要注意的是，它使用 lxml.etree

 而不是上游 ElementTree）：

import lxml.etree as etree

el = etree.fromstring('<root><item><subitem><subsubitem/></subitem></item></root>')
for child in el.xpath('.//subsubitem | .//subitem'):
  child.getparent().remove(child)

Answer 3

https://docs.python.org/3/library/xml.etree.elementtree.html#element-objects

https://docs.python.org/3/library/xml.etree.elementtree.html#modifying-an-xml-file

请注意，迭代时并发修改可能会导致 问题，就像迭代和修改 Python 列表或 听写。

此脚本将在 3.10 上运行：

    #!/usr/bin/python
    import xml.etree.ElementTree as ET
    
    def print_xmltree(root):
        xmlstr = ET.tostring(root, encoding="utf-8", method="xml")
        print(xmlstr.decode("utf-8"))
    
    def recursive_xml(parent, depth):
        #print(depth * "  ", parent.findall('./'))
        for child in parent.findall('./'):
            if child.tag == 'subitem' or child.tag == 'subsubitem':
                parent.remove(child)
            else:
                recursive_xml(child, depth + 1)
                    
    xml_data = """<?xml version="1.0" encoding="UTF-8"?>
    <tree>
        <category title="Item 1">item 1 text
            <subitem title="subitem1">subitem11 text</subitem>
            <subitem title="subitem2">subitem12 text</subitem>
            <sibetum title="subitem3">subitem13 text</sibetum>
                <subsubitem title="subsubitem1">subsubitem211 text</subsubitem>
        </category>
        <category title="Item 2">item 2 text
            <subitem title="subitem1">subitem21 text</subitem>
            <subitem title="subitem2">subitem22 text</subitem>
                <subsubitem title="subsubitem1">subsubitem211 text</subsubitem>
                <sobsobitem title="subsubitem2">wrong tag</sobsobitem>
        </category>
        <category title="Item 3">item 3 text
        </category>
    </tree>"""    
    
    #root = ET.parse('test.xml').getroot() # from file
    root = ET.fromstring(xml_data) # from variable
    
    recursive_xml(root, 0)
    print_xmltree(root)
    # Note that sobsobitem was forced up in hierachy and that parent tag for subsubitem did not matter (sibetum).
    
    wait = input("Press Enter to Exit.")

这将输出：

<tree>
    <category title="Item 1">item 1 text
        <sibetum title="subitem3">subitem13 text</sibetum>
            </category>
    <category title="Item 2">item 2 text
        <sobsobitem title="subsubitem2">wrong tag</sobsobitem>
    </category>
    <category title="Item 3">item 3 text
    </category>
</tree>