ElementTree - findall to recursively select all child elements

Question

Python code:

import xml.etree.ElementTree as ET
root = ET.parse(\"h.xml\")
print root.findall(\'saybye\')

h.xml code:

Answer 1

Element.findall() finds only elements with a tag which are direct children of the current element.

we need to recursively traversing all childrens to find elements matching your element.

def find_rec(node, element):
    def _find_rec(node, element, result):
        for el in node.getchildren():
            _find_rec(el, element, result)
        if node.tag == element:
            result.append(node)
    res = list()
    _find_rec(node, element, res)
    return res

Answer 2

Quoting findall,

Element.findall() finds only elements with a tag which are direct children of the current element.

Since it finds only the direct children, we need to recursively find other children, like this

>>> import xml.etree.ElementTree as ET
>>> 
>>> def find_rec(node, element, result):
...     for item in node.findall(element):
...         result.append(item)
...         find_rec(item, element, result)
...     return result
... 
>>> find_rec(ET.parse("h.xml"), 'saybye', [])
[<Element 'saybye' at 0x7f4fce206710>, <Element 'saybye' at 0x7f4fce206750>, <Element 'saybye' at 0x7f4fce2067d0>]

Even better, make it a generator function, like this

>>> def find_rec(node, element):
...     for item in node.findall(element):
...         yield item
...         for child in find_rec(item, element):
...             yield child
... 
>>> list(find_rec(ET.parse("h.xml"), 'saybye'))
[<Element 'saybye' at 0x7f4fce206a50>, <Element 'saybye' at 0x7f4fce206ad0>, <Element 'saybye' at 0x7f4fce206b10>]

Answer 3

From version 2.7 on, you can use xml.etree.ElementTree.Element.iter:

import xml.etree.ElementTree as ET
root = ET.parse("h.xml")
print root.iter('saybye')

See 19.7. xml.etree.ElementTree — The ElementTree XML API

Answer 4

If you aren't afraid of a little XPath, you can use the // syntax that means find any descendant node:

import xml.etree.ElementTree as ET
root = ET.parse("h.xml")
print root.findall('.//saybye')

Full XPath isn't supported, but here's the list of what is: https://docs.python.org/2/library/xml.etree.elementtree.html#supported-xpath-syntax