How to get grandchild elements from Elementtree in python

问题

Say I have an XML code like this one:

<root>
    <a>
        <b>
           ....
        </b>
        <c>
           ....
        </c>
        <d>
           ....
        </d>
    </a>
    <d><c></c><a></a></d>
</root>

Is there a function to get the grandchildren elements given a certain child node? Foe example, in the XML code above, if I pass 'd', I would like it to return 'c' and 'a'.

I tried getChildren(), but I guess this returns attributes, but not the children elements. I don't even have attributes btw.

Thank you.

回答1:

The root element is iterable:

>>> import xml.etree.ElementTree as ET
>>> xml = "<root><a><b>....</b><c>....</c><d>....</d></a><d><c><a></a></c></d></root>"
>>> root = ET.fromstring(xml)
>>> root
<Element 'root' at 0x7fa86a7ea610>
>>> for child in root:
...     print child
... 
<Element 'a' at 0x7fa86a7ea650>
<Element 'd' at 0x7fa86a7ea810>

Getting specific grandchild elements:

>>> root = ET.fromstring(xml)
>>> root.find("d").getchildren()
[<Element 'c' at 0x7fce44939650>, <Element 'a' at 0x7fce44939690>]

If you want the tag rather than the ElementTree object:

>>> [e.tag for e in  root.find("d").getchildren()]
['c', 'a']

Note that <Element 'c' at 0x7fce44939650> represents an ElementTree Element object (same as root), whose API is defined in the docs

回答2:

Given that root is the root of your tree:

>>> [grchild for child in root for grchild in child]
[<Element 'b' at 0xb6cbad4c>, <Element 'c' at 0xb6cbaedc>,
<Element 'd' at 0xb6cbad24>, <Element 'c' at 0xb6cbaaa4>]

Ok so let's write a recursive function the Haskell way:

def recurse(node):
    for child in node:
        print(child)
        recurse(child)

>>> node = root.find('d')
>>> recurse(node)
<Element 'c' at 0xb6cbaaa4>
<Element 'a' at 0xb6cbac0c>

回答3:

Assuming you have already, parsed the document, [i.getchildren() for i in root.findall('d')] is probably what you want!

To be more generic, you can have a function


def getGrandChildOfTag(tagName, root):
    return [i.getchildren() for i in root.findall(tagName)]

来源：https://stackoverflow.com/questions/17294093/how-to-get-grandchild-elements-from-elementtree-in-python

标签

python

elementtree